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Artigos de revistas sobre o tema "Baryons"

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Autor: Grafiati

Publicado: 4 de junho de 2021

Última modificação: 8 de junho de 2024

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1

GARCIA-RECIO, C., L. L. SALCEDO, D. GAMERMANN, J. NIEVES, O. ROMANETS e L. TOLOS. "CHARMING BARYONS". International Journal of Modern Physics: Conference Series 26 (janeiro de 2014): 1460124. http://dx.doi.org/10.1142/s2010194514601240.

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We study odd-parity baryonic resonances with one heavy and three light flavors, dynamically generated by meson-baryon interactions. Special attention is paid to Heavy Quark Spin Symmetry (HQSS), hence pseudoscalar and vector mesons and baryons with Jπ = 1/2+ and 3/2+ are considered as constituent hadrons. For the hidden-charm sector ([Formula: see text]), the meson-baryon Lagrangian with Heavy Flavor Symmetry is constructed by a minimal extension of the SU(3) Weinberg-Tomozawa (WT) Lagrangian to fulfill HQSS, such that not new parameters are needed. This interaction can be presented in different formal ways: as a Field Lagrangian, as Hadron creation-annihilation operators, as SU(6)×HQSS group projectors and as multichannel matrices. The multichannel Bethe-Salpeter equation is solved for odd-parity light baryons, hidden-charm N and Δ and Beauty Baryons (Λb). Results of calculations with this model are shown in comparison with other models and experimental values for baryonic resonances.

2

LEDDIG, TORSTEN. "INVESTIGATION OF B-MESON DECAYS INTO BARYONS WITH THE BABAR DETECTOR". International Journal of Modern Physics A 26, n.º 03n04 (10 de fevereiro de 2011): 545–48. http://dx.doi.org/10.1142/s0217751x11051986.

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We report on investigations of B-meson decays into baryons with the BABAR detector. The comparison of different decay channels reveals that higher multiplicities are preferred for these decays. Furthermore, an enhancement in the invariant baryon-antibaryon mass distribution can be observed in several baryonic decay modes. In addition, the study of baryon resonances seen in baryonic B-meson decays is presented.

3

Kostyuk, Ivan, Robert Lilow e Matthias Bartelmann. "Baryon-photon interactions in Resummed Kinetic Field Theory". Journal of Cosmology and Astroparticle Physics 2023, n.º 09 (1 de setembro de 2023): 032. http://dx.doi.org/10.1088/1475-7516/2023/09/032.

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Abstract We explore how interactions between baryons and photons can be incorporated into Kinetic Field Theory (KFT), a description of cosmic structure formation based on classical Hamiltonian particle dynamics. In KFT, baryons are described as effective mesoscopic particles which represent fluid elements governed by the hydrodynamic equations. In this paper, we modify the mesoscopic particle model to include pressure effects exerted on baryonic matter through interactions with photons. As a proof of concept, we use this extended mesoscopic model to describe the tightly coupled baryon-photon fluid between matter-radiation equality and recombination. We show that this model can qualitatively reproduce the formation of baryon-acoustic oscillations in the cosmological power spectrum.

4

Dominguez-Tenreiro, Rosa, e Gustavo Yepes. "On the Possibility of a Higher Baryonic Contribution to Dark Matter". Symposium - International Astronomical Union 130 (1988): 592. http://dx.doi.org/10.1017/s0074180900137180.

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The most stringent constraint against baryonic dark matter is provided by primordial nucleosynthesis. Agreement between theory and observations is reachedonly for a limited range of the baryon-to-photon ratio ‘LR, namely , which implies that, in standard cosmological frameworks, the universe cannot be closed by baryons.

5

Ghalenovi, Zahra. "Study of Heavy Strange Baryons in a Hypercentral Quark Model". International Journal of Modern Physics: Conference Series 46 (janeiro de 2018): 1860037. http://dx.doi.org/10.1142/s2010194518600376.

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In this work, we study the properties of the heavy baryons with strangeness employing a constituent quark model in the hypercentral approach. The potential model considers the interactions arising the one-gluon exchange, Goldstone boson exchange and confinement, aspects of underlying theory, quantum chromodynamics (QCD). By solving three-body Schrodinger equation of baryonic system, we obtain the ground as well as the corresponding energy eigenvalues of the system. Using the obtained energies, we calculate the baryon spectrum. We extend our scheme to predict the radiative decay width of the charm baryons. A comparison of our results with those of other works and experimental data is also presented.

6

Wright, Ruby J., Claudia del P. Lagos, Chris Power e Peter D. Mitchell. "The impact of stellar and AGN feedback on halo-scale baryonic and dark matter accretion in the eagle simulations". Monthly Notices of the Royal Astronomical Society 498, n.º 2 (14 de agosto de 2020): 1668–92. http://dx.doi.org/10.1093/mnras/staa2359.

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ABSTRACT We use the eagle suite of hydrodynamical simulations to analyse accretion rates (and the breakdown of their constituent channels) on to haloes over cosmic time, comparing the behaviour of baryons and dark matter (DM). We also investigate the influence of sub-grid baryon physics on halo-scale inflow, specifically the consequences of modelling radiative cooling, as well as feedback from stars and active galactic nuclei (AGNs). We find that variations in halo baryon fractions at fixed mass (particularly their circumgalactic medium gas content) are very well correlated with variations in the baryon fraction of accreting matter, which we show to be heavily suppressed by stellar feedback in low-mass haloes, Mhalo ≲ 1011.5 M⊙. Breaking down accretion rates into first infall, recycled, transfer, and merger components, we show that baryons are much more likely to be smoothly accreted than to have originated from mergers when compared to DM, finding (averaged across halo mass) a merger contribution of $\approx 6{{\ \rm per\ cent}}$ for baryons, and $\approx 15{{\ \rm per\ cent}}$ for DM at z ≈ 0. We also show that the breakdown of inflow into different channels is strongly dependent on sub-grid physics, particularly the contribution of recycled accretion (accreting matter that has been previously ejected from progenitor haloes). Our findings highlight the dual role that baryonic feedback plays in regulating the evolution of galaxies and haloes: by (i) directly removing gas from haloes, and (ii) suppressing gas inflow to haloes.

7

Khan, Mehbub, Yun Hao e Jong-Ping Hsu. "Baryonic Force for Accelerated Cosmic Expansion and Generalized U1b Gauge Symmetry in Particle-Cosmology". EPJ Web of Conferences 168 (2018): 04004. http://dx.doi.org/10.1051/epjconf/201816804004.

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Based on baryon charge conservation and a generalized Yang-Mills symmetry for Abelian (and non-Abelian) groups, we discuss a new baryonic gauge field and its linear potential for two point-like baryon charges. The force between two point-like baryons is repulsive, extremely weak and independent of distance. However, for two extended baryonic systems, we have a dominant linear force α r. Thus, only in the later stage of the cosmic evolution, when two baryonic galaxies are separated by an extremely large distance, the new repulsive baryonic force can overcome the gravitational attractive force. Such a model provides a gauge-field-theoretic understanding of the late-time accelerated cosmic expansion. The baryonic force can be tested by measuring the accelerated Wu-Doppler frequency shifts of supernovae at different distances.

8

HOSAKA, A., H. TOKI e M. TAKAYAMA. "BARYON SPECTRA IN DEFORMED OSCILLATOR QUARK MODEL". Modern Physics Letters A 13, n.º 21 (10 de julho de 1998): 1699–707. http://dx.doi.org/10.1142/s0217732398001777.

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We study theoretically the baryon spectra in terms of a deformed oscillator quark (DOQ) model. This model is motivated by confinement of quarks and chiral symmetry breaking, which are the most important nonperturbative phenomena of QCD. The minimization of the DOQ Hamiltonian with respect to the deformation for each principal quantum number results in deformations for the intrinsic states of excited baryonic states. We find that the resulting baryon spectra agree very well with the existing experimental data including SU(3) baryons. The spatial deformation of the baryonic excited states carry useful information on the quark confinement and provide a clue to understand the confining mechanism.

9

McGaugh, Stacy S. "The Halo by Halo Missing Baryon Problem". Proceedings of the International Astronomical Union 3, S244 (junho de 2007): 136–45. http://dx.doi.org/10.1017/s1743921307013920.

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AbstractThe global missing baryon problem – that the sum of observed baryons falls short of the number expected form BBN – is well known. In addition to this, there is also a local missing baryon problem that applies to individual dark matter halos. This halo by halo missing baryon problem is such that the observed mass fraction of baryons in individual galaxies falls short of the cosmic baryon fraction. This deficit is a strong function of circular velocity. I give an empirical estimate of this function, and note the presence of a critical scale of ~ 900 km s−1 therein. I also briefly review Ωb from BBN, highlighting the persistent tension between lithium and the CMB, and discuss some pros and cons of individual galaxies and clusters of galaxies as potential reservoirs of dark baryons.

10

PAGE, PHILIP R. "HYBRID AND CONVENTIONAL BARYONS IN THE FLUX-TUBE AND QUARK MODELS". International Journal of Modern Physics A 20, n.º 08n09 (10 de abril de 2005): 1791–96. http://dx.doi.org/10.1142/s0217751x05023347.

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The status of conventional baryon flux-tubes and hybrid baryons is reviewed. Recent surprises are that a model prediction indicates that hybrid baryons are very weakly produced in glue-rich Ψ decays, and an analysis of electro-production data concludes that the Roper resonance is not a hybrid baryon. The baryon decay flux-tube overlap has been calculated in the flux-tube model, and is discussed here. The behavior of the overlap follows naïve expectations.

11

Schramm, D. N. "Cosmological Dark Matter". International Journal of Modern Physics D 06, n.º 04 (agosto de 1997): 393–407. http://dx.doi.org/10.1142/s0218271897000236.

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The basic arguments for cosmological dark matter are reviewed. It is shown that the Big Bange Nucleosynthesis constraints on the cosmological baryon density, when compared with dynamical arguments, demonstrate that the bulk of the baryons are dark and also that the bulk of the matter in the universe is nonbaryonic. The recent extragalactic deuterium observations as well as the other light element abundances were examined in detail as is the argument on the number of neutrino flavors. Arguments from recent MACHO/EROS observations of halo dark matter seem to imply that at least some of the dark baryons are in the halos of galaxies. Comparison of baryonic density arguments with recent x-ray cluster data is also made. Discussion of the interface of density and age arguments is also presented.

12

Matskevich, Elena. "Bottom (70,1-) baryon multiplet". E3S Web of Conferences 164 (2020): 01008. http://dx.doi.org/10.1051/e3sconf/202016401008.

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The aim of this paper is to derive systems of equations for the amplitudes for the case of negative parity (70,1-) bottom nonstrange baryons and to calculate the masses of these particles. In order to calculate masses of (70,1-) bottom baryons we use the relativistic quark model. The relativistic three-quark equations of the (70,1-) bottom baryon multiplet are derived in the framework of the dispersion relation technique. The relativistic three-quark equations of the (70,1-) bottom baryon multiplet are derived. The approximate solutions of these equations using the method based on the extraction of leading singularities of the amplitude are obtained. The masses of 21 baryons are predicted.

13

RICHARD, JEAN-MARC. "BARYON SPECTROSCOPY AND HEAVY QUARKS". International Journal of Modern Physics: Conference Series 02 (janeiro de 2011): 168–72. http://dx.doi.org/10.1142/s2010194511000754.

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Two topics are briefly reviewed in this talk: the decay of flavored hadrons or quarkonium states involving a baryon–antibaryon pair, and the spectroscopy of heavy baryons containing one, two or three heavy quarks. Some prospects for exotic heavy baryons are also discussed.

14

Martinsson, Thomas, Marc Verheijen, Matthew Bershady, Kyle Westfall, David Andersen e Rob Swaters. "Mass distributions in disk galaxies". Proceedings of the International Astronomical Union 11, S321 (março de 2016): 283. http://dx.doi.org/10.1017/s1743921316011169.

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AbstractWe present results on luminous and dark matter mass distributions in disk galaxies from the DiskMass Survey. As expected for normal disk galaxies, stars dominate the baryonic mass budget in the inner region of the disk; however, at about four optical scale lengths (hR) the atomic gas starts to become the dominant contributor. Unexpectedly, we find the total baryon to dark-matter fraction within a galaxy stays nearly constant with radius from 1hR out to at least 6hR, with a baryon fraction of 15–50% among galaxies. On average, only one third of the mass within 2.2hR in a disk galaxy is baryonic and these baryons appear to have had only a minor effect on the distribution of the dark matter.

15

Ciepał, Izabela. "Studies of Time-like Electromagnetic Structure of Baryons with HADES". EPJ Web of Conferences 291 (2024): 01011. http://dx.doi.org/10.1051/epjconf/202429101011.

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We present results of studies of Dalitz decays of baryon resonances (R→Ne+e−) in proton-proton (pp) and pion-proton (πp) collisions performed by the HADES collaboration. They provided the first measurement of electromag netic transition form factors of baryons in the time-like region and contribute to the understanding of the photon-baryon coupling and the role of Vector Dom inance Model in a baryonic sector. We discuss also implications of the results to the understanding of the emissivity of dense and hot QCD matter created in heavy-ion collisions and the role played by the in-medium modification of the ρ meson. Further prospects for future studies with pion beams at GSI with HADES are given in the outlook.

16

DMITRAŠINOVIĆ, V., KEITARO NAGATA e ATSUSHI HOSAKA. "CHIRAL PROPERTIES OF BARYON INTERPOLATING FIELDS". Modern Physics Letters A 23, n.º 27n30 (30 de setembro de 2008): 2381–84. http://dx.doi.org/10.1142/s0217732308029423.

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We study the chiral transformation properties of all possible local (non-derivative) interpolating field operators for baryons consisting of three quarks with two flavors, assuming good isospin symmetry. We derive and use the relations/identities among the baryon operators with identical quantum numbers that follow from the combined color, Dirac and isospin Fierz transformations. These relations reduce the number of independent baryon operators with any given spin and isospin. The Fierz identities also effectively restrict allowed baryon chiral multiplets. It turns out that the chiral multiplets of the baryons are equivalent to their Lorentz representation.

17

Bian, Jian-Ming, Vladimir Bytev, Ying Chen, Hong-Ying Jin, Shan Jin, Hu Qin, Xiao-Yan Shen et al. "Chapter 10 Baryon Spectrum". International Journal of Modern Physics A 24, supp01 (maio de 2009): 233–50. http://dx.doi.org/10.1142/s0217751x09046527.

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18

Meadows, Brian T. "Charm Decays at B Factories". International Journal of Modern Physics A 21, n.º 27 (30 de outubro de 2006): 5436–44. http://dx.doi.org/10.1142/s0217751x06034574.

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Recent results relating to charm baryon and meson decays from the Belle and BABAR experiments are presented. In addition to recent observations for charm hyperons, evidence for a new charm baryon state, the Λc(2940), observed in its decay to D0p is also reported. No evidence for doubly charmed baryons is seen in e+e- interactions. A measurement of the spin of the Ω- hyperon is made using decays of the [Formula: see text] and [Formula: see text] baryons. On the assumption that the spin of the parent baryons are J = 1/2, the assignment J = 3/2 is confirmed and both J = 1/2 and also higher spins are excluded. New results on rare, Cabibbo-suppressed decays of charm mesons are also presented.

19

ISHII, TAKAAKI. "LONG-DISTANCE PROPERTIES OF BARYONS IN THE SAKAI-SUGIMOTO MODEL". International Journal of Modern Physics: Conference Series 21 (janeiro de 2013): 187–88. http://dx.doi.org/10.1142/s2010194513009732.

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We reconsider the realization of baryons in the Sakai-Sugimoto model. It has previously been shown that, at least with the standard approach to calculations of baryon properties in the theory, one does not reproduce some model-independent predictions for the behavior of baryon electromagnetic form factors connected with long-range pion physics. It is suspected that the pion contributions has been dropped because of the linearization approximations. We study the long-range properties of baryons without relying on the approximations. The baryon solution we obtain gives the correct result for the model-independent ratio of the form factors.

20

Karthein, Jamie M., Volker Koch, Claudia Ratti e Volodymyr Vovchenko. "Constraints on hadron resonance gas interactions via first-principles Lattice QCD susceptibilities". EPJ Web of Conferences 276 (2023): 03014. http://dx.doi.org/10.1051/epjconf/202327603014.

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We investigate extensions of the Hadron Resonance Gas (HRG) Model beyond the ideal case by incorporating both attractive and repulsive interactions into the model. When considering additional states exceeding those measured with high confidence by the Particle Data Group, attractive corrections to the overall pressure in the HRG model are imposed. On the other hand, we also apply excluded-volume corrections, which ensure there is no overlap of baryons by turning on repulsive (anti)baryon-(anti)baryon interactions. We emphasize the complementary nature of these two extensions and identify combinations of conserved charge susceptibilities that allow us to constrain them separately. In particular, we find interesting ratios of susceptibilities that are sensitive to one correction and not the other. This allows us to constrain the excluded volume and particle spectrum effects separately. Analysis of the available lattice results suggests the presence of both the extra states in the baryonstrangeness sector and the repulsive baryonic interaction, with indications that hyperons have a smaller repulsive core than non-strange baryons. We note that these results are interesting for heavy-ion-collision systems at both the LHC and RHIC.

21

Russ, James S. "New Results on Heavy Flavor Baryons". International Journal of Modern Physics A 21, n.º 27 (30 de outubro de 2006): 5482–87. http://dx.doi.org/10.1142/s0217751x06034641.

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Heavy flavor baryons are attractive systems for testing effective theories for weak lifetime and decay systematics. Recently, new experimental results have mitigated one historic problem in the weak lifetime systematics and continued another. The charm baryon system continues to show new high mass, narrow states well isolated from one another. The spectroscopy of these states will challenge new advances in lattice gauge theoretic calculations of baryon structure. Double charm baryons still are seen only by SELEX, which showed a new [Formula: see text] candidate. High-sensitivity searches by BELLE and BaBar show only featureless background.

22

Oudichhya, Juhi, Keval Gandhi e Ajay Kumar Rai. "Mass spectra of Ξ_cc, Ξ_bc, Ω_cc, and Ω_bc baryons in Regge phenomenology". Physica Scripta 97, n.º 5 (28 de março de 2022): 054001. http://dx.doi.org/10.1088/1402-4896/ac5de7.

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Abstract In this article, we study the mass spectra of baryons containing two heavy quarks; charm-charm (cc) and bottom-charm (bc) with a light quark (u, d, s) within the framework of Regge phenomenology. With the assumption of linear Regge trajectories we have derived the relations between slope ratios, intercepts, and baryon masses. Using these relations, the ground state masses of Ξ cc , Ξ bc , Ω cc , and Ω bc baryons are obtained. The values of Regge slopes and Regge intercepts are extracted for these baryons to estimate the excited state masses in both the (J, M 2) and (n, M 2) planes. Our obtained results are compared with the experimental observations where available and other theoretical predictions, which could be a valuable addition to the interpretations of experimentally unknown heavy baryon spectra.

23

OSET, E., A. RAMOS, E. J. GARZON, R. MOLINA, L. TOLOS, C. W. XIAO, J. J. WU e B. S. ZOU. "INTERACTION OF VECTOR MESONS WITH BARYONS AND NUCLEI". International Journal of Modern Physics E 21, n.º 11 (novembro de 2012): 1230011. http://dx.doi.org/10.1142/s0218301312300111.

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After some short introductory remarks on particular issues on the vector mesons in nuclei, in this paper, we present a short review of recent developments concerning the interaction of vector mesons with baryons and with nuclei from a modern perspective using the local hidden gauge formalism for the interaction of vector mesons. We present results for the vector–baryon interaction and in particular for the resonances which appear as composite states, dynamically generated from the interaction of vector mesons with baryons, taking also the mixing of these states with pseudoscalars and baryons into account. We then venture into the charm sector, reporting on hidden charm baryon states around 4400 MeV, generated from the interaction of vector mesons and baryons with charm, which have a strong repercussion on the properties of the J/ΨN interaction. We also address the interaction of K* with nuclei and make suggestions to measure the predicted huge width in the medium by means of transparency ratio. The formalism is extended to study the phenomenon of J/ψ suppression in nuclei via J/ψ photo-production reactions.

24

PAULINI, MANFRED. "PROPERTIES OF HEAVY B HADRONS". International Journal of Modern Physics A 24, n.º 24 (30 de setembro de 2009): 4413–35. http://dx.doi.org/10.1142/s0217751x09046114.

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We review recent measurements of heavy B hadron states including masses and lifetimes of the [Formula: see text] meson as well as excited B states [Formula: see text]. We discuss properties of the [Formula: see text] meson such as lifetime, lifetime difference ΔΓs/Γs and CP violation in [Formula: see text] decays. We also summarize new measurements of the masses and lifetimes of bottom baryons including the [Formula: see text] baryon, the Σb baryon states as well as the [Formula: see text] and [Formula: see text] baryons.

25

Buchmann, Alfons J. "Ernest Henley and the shape of baryons". International Journal of Modern Physics E 27, n.º 12 (dezembro de 2018): 1840009. http://dx.doi.org/10.1142/s0218301318400098.

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Calculations of pion–baryon couplings, baryon quadrupole and octupole moments, baryon spin and orbital angular momentum done in collaboration with Ernest Henley are reviewed. A common theme of this work is the shape of baryons. Also, a personal account of my work with Ernest Henley during the period 1999–2013 is given.

26

Voit, G. Mark, Benjamin D. Oppenheimer, Eric F. Bell, Bryan Terrazas e Megan Donahue. "Black Hole Growth, Baryon Lifting, Star Formation, and IllustrisTNG". Astrophysical Journal 960, n.º 1 (19 de dezembro de 2023): 28. http://dx.doi.org/10.3847/1538-4357/ad0039.

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Abstract Quenching of star formation in the central galaxies of cosmological halos is thought to result from energy released as gas accretes onto a supermassive black hole. The same energy source also appears to lower the central density and raise the cooling time of baryonic atmospheres in massive halos, thereby limiting both star formation and black hole growth, by lifting the baryons in those halos to greater altitudes. One predicted signature of that feedback mechanism is a nearly linear relationship between the central black hole’s mass (M BH) and the original binding energy of the halo’s baryons. We present the increasingly strong observational evidence supporting a such a relationship, showing that it extends up to halos of mass M halo ∼ 1014 M ⊙. We then compare current observational constraints on the M BH–M halo relation with numerical simulations, finding that black hole masses in IllustrisTNG appear to exceed those constraints at M halo < 1013 M ⊙ and that black hole masses in EAGLE fall short of observations at M halo ∼ 1014 M ⊙. A closer look at IllustrisTNG shows that quenching of star formation and suppression of black hole growth do indeed coincide with black hole energy input that lifts the halo’s baryons. However, IllustrisTNG does not reproduce the observed M BH–M halo relation because its black holes gain mass primarily through accretion that does not contribute to baryon lifting. We suggest adjustments to some of the parameters in the IllustrisTNG feedback algorithm that may allow the resulting black hole masses to reflect the inherent links between black hole growth, baryon lifting, and star formation among the massive galaxies in those simulations.

27

Lu, Tianhuan, e Zoltán Haiman. "The impact of baryons on cosmological inference from weak lensing statistics". Monthly Notices of the Royal Astronomical Society 506, n.º 3 (10 de julho de 2021): 3406–17. http://dx.doi.org/10.1093/mnras/stab1978.

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ABSTRACT As weak lensing surveys are becoming deeper and cover larger areas, information will be available on small angular scales down to the arcmin level. To extract this extra information, accurate modelling of baryonic effects is necessary. In this work, we adopt a baryonic correction model, which includes gas both bound inside and ejected from dark matter (DM) haloes, a central galaxy, and changes in the DM profile induced by baryons. We use this model to incorporate baryons into a large suite of DM-only N-body simulations, covering a grid of 75 cosmologies in the Ωm–σ8 parameter space. We investigate how baryons affect Gaussian and non-Gaussian weak lensing statistics and the cosmological parameter inferences from these statistics. Our results show that marginalizing over baryonic parameters degrades the constraints in Ωm–σ8 space by a factor of 2–5 compared to those with baryonic parameters fixed. We also find that combining the lensing power spectrum and peak counts can break the degeneracy between cosmological and baryonic parameters and mitigate the impact of the uncertainty in baryonic physics.

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Khan, Shahid, Viktor Klochkov, Olha Lavoryk, Oleksii Lubynets, Ali Imdad Khan, Andrea Dubla e Ilya Selyuzhenkov. "Machine Learning Application for Λ Hyperon Reconstruction in CBM at FAIR". EPJ Web of Conferences 259 (2022): 13008. http://dx.doi.org/10.1051/epjconf/202225913008.

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The Compressed Baryonic Matter experiment at FAIR will investigate the QCD phase diagram in the region of high net-baryon densities. Enhanced production of strange baryons, such as the most abundantly produced Λ hyperons, can signal transition to a new phase of the QCD matter. In this work, the CBM performance for reconstruction of the Λ hyperon via its decay to proton and π− is presented. Decay topology reconstruction is implemented in the Particle-Finder Simple (PFSimple) package with Machine Learning algorithms providing effcient selection of the decays and high signal to background ratio.

29

CIARCELLUTI, PAOLO. "COSMOLOGY WITH MIRROR DARK MATTER I: LINEAR EVOLUTION OF PERTURBATIONS". International Journal of Modern Physics D 14, n.º 02 (fevereiro de 2005): 187–221. http://dx.doi.org/10.1142/s0218271805006213.

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This is the first paper of a series devoted to the study of the cosmological implications of the parallel mirror world with the same microphysics as the ordinary one, but having smaller temperature, with a limit set by the BBN constraints. The difference in temperature of the ordinary and mirror sectors generates shifts in the key epochs for structure formation, which proceeds in the mirror sector under different conditions. We consider adiabatic scalar primordial perturbations as an input and analyze the trends of all the relevant scales for structure formation (Jeans length and mass, Silk scale, horizon scale) for both ordinary and mirror sectors, comparing them with the CDM case. These scales are functions of the fundamental parameters of the theory (the temperature of the mirror plasma and the amount of mirror baryonic matter), and in particular they are influenced by the difference between the cosmological key epochs in the two sectors. Then we use a numerical code to compute the evolution in linear regime of density perturbations for all the components of a Mirror Universe: ordinary baryons and photons, mirror baryons and photons, and possibly cold dark matter. We analyze the evolution of the perturbations for different values of mirror temperature and baryonic density, and obtain that for x=T′/T less than a typical value x eq , for which the mirror baryon–photon decoupling happens before the matter–radiation equality, mirror baryons are equivalent to the CDM for the linear structure formation process. Indeed, the smaller the value of x, the closer mirror dark matter resembles standard cold dark matter during the linear regime.

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Borrow, Josh, Daniel Anglés-Alcázar e Romeel Davé. "Cosmological baryon transfer in the simba simulations". Monthly Notices of the Royal Astronomical Society 491, n.º 4 (9 de dezembro de 2019): 6102–19. http://dx.doi.org/10.1093/mnras/stz3428.

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ABSTRACT We present a framework for characterizing the large-scale movement of baryons relative to dark matter in cosmological simulations, requiring only the initial conditions and final state of the simulation. This is performed using the spread metric that quantifies the distance in the final conditions between initially neighbouring particles, and by analysing the baryonic content of final haloes relative to that of the initial Lagrangian regions (LRs) defined by their dark matter component. Applying this framework to the simba cosmological simulations, we show that 40 per cent (10 per cent) of cosmological baryons have moved $\gt 1\, h^{-1}\, {\rm Mpc}{}$ ($3\, h^{-1}\, {\rm Mpc}{}$) by z = 0, primarily due to entrainment of gas by jets powered by an active galactic nucleus, with baryons moving up to $12\, h^{-1}\, {\rm Mpc}{}$ away in extreme cases. Baryons decouple from the dynamics of the dark matter component due to hydrodynamic forces, radiative cooling, and feedback processes. As a result, only 60 per cent of the gas content in a given halo at z = 0 originates from its LR, roughly independent of halo mass. A typical halo in the mass range Mvir = 1012–1013 M⊙ only retains 20 per cent of the gas originally contained in its LR. We show that up to 20 per cent of the gas content in a typical Milky Way-mass halo may originate in the region defined by the dark matter of another halo. This inter-Lagrangian baryon transfer may have important implications for the origin of gas and metals in the circumgalactic medium of galaxies, as well as for semi-analytic models of galaxy formation and ‘zoom-in’ simulations.

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Tazimi, N., e P. Sadeghi Alavijeh. "Investigation of Baryons in the Hypercentral Quark Model". Advances in High Energy Physics 2021 (21 de outubro de 2021): 1–11. http://dx.doi.org/10.1155/2021/7713697.

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In the present study, we consider baryons as three-body bound systems according to the hypercentral constituent quark model in configuration space and solve the three-body Klein-Gordon equation. Then, we analyze perturbative spin-dependent and isospin-dependent interaction effects. To find the analytical solution, we use screened potential and calculate the eigenfunctions and eigenvalues of some baryons. We consider exclusive semileptonic decays of bottom and charm baryons and apply the differential decay width with the Isgur-Wise function and arrive at the rates for some semileptonic baryon decays. The results prove more enhanced compared to recent works and comply well with the experimental data.

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Friesen, Alexandra, e Yuriy Kalinovsky. "Diquarks and Λ0/π+, Ξ−/π+ Ratios in the Framework of the EPNJL Model". Particles 6, n.º 4 (10 de outubro de 2023): 876–85. http://dx.doi.org/10.3390/particles6040056.

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The applicability of the effective models to the description of baryons and the behaviour of ratios of strange baryons to pions is discussed. In the framework of the EPNJL model, the Bethe–Salpeter equation is used to find masses of baryons, which are considered to be in a diquark-quark state. Baryon melting is discussed at a finite chemical potential, and a flavor dependence of the hadronic deconfinement temperature is pointed out. It is shown that the description of the diquark-quark state at finite chemical potential is limited due to the occurrence of Bose condensate. This effect is strongly manifested in the description of light diquarks and baryons. Both the Λ0/π+ and Ξ−/π+ ratios show a sharp behaviour as functions of the T/μB variable, where T and μB are calculated along the melting lines.

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Castro, T., S. Borgani, M. Costanzi, J. Dakin, K. Dolag, A. Fumagalli, A. Ragagnin et al. "Euclid preparation". Astronomy & Astrophysics 685 (maio de 2024): A109. http://dx.doi.org/10.1051/0004-6361/202348388.

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The Euclid photometric survey of galaxy clusters stands as a powerful cosmological tool, with the capacity to significantly propel our understanding of the Universe. Despite being subdominant to dark matter and dark energy, the baryonic component of our Universe holds substantial influence over the structure and mass of galaxy clusters. This paper presents a novel model that can be used to precisely quantify the impact of baryons on the virial halo masses of galaxy clusters using the baryon fraction within a cluster as a proxy for their effect. Constructed on the premise of quasi-adiabaticity, the model includes two parameters, which are calibrated using non-radiative cosmological hydrodynamical simulations, and a single large-scale simulation from the Magneticum set, which includes the physical processes driving galaxy formation. As a main result of our analysis, we demonstrate that this model delivers a remarkable 1% relative accuracy in determining the virial dark matter-only equivalent mass of galaxy clusters starting from the corresponding total cluster mass and baryon fraction measured in hydrodynamical simulations. Furthermore, we demonstrate that this result is robust against changes in cosmological parameters and against variation of the numerical implementation of the subresolution physical processes included in the simulations. Our work substantiates previous claims regarding the impact of baryons on cluster cosmology studies. In particular, we show how neglecting these effects would lead to biased cosmological constraints for a Euclid-like cluster abundance analysis. Importantly, we demonstrate that uncertainties associated with our model arising from baryonic corrections to cluster masses are subdominant when compared to the precision with which mass–observable (i.e. richness) relations will be calibrated using Euclid and to our current understanding of the baryon fraction within galaxy clusters.

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EBERT, DIETMAR, THORSTEN FELDMANN, CHRISTIANE KETTNER e HUGO REINHARDT. "HEAVY BARYONS IN THE QUARK-DIQUARK PICTURE". International Journal of Modern Physics A 13, n.º 07 (20 de março de 1998): 1091–113. http://dx.doi.org/10.1142/s0217751x98000482.

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We describe heavy baryons as bound states of a quark and a diquark. For this purpose we derive the Faddeev equation for baryons containing a single heavy quark from a Nambu–Jona–Lasinio type of model which is appropriately extended to include also heavy quarks. The latter are treated in the heavy mass limit. The heavy baryon Faddeev equation is then solved using a static approximation for the exchanged quark.

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ANISOVICH, A. V., V. V. ANISOVICH, M. A. MATVEEV, V. A. NIKONOV, A. V. SARANTSEV e T. O. VULFS. "SEARCHING FOR THE QUARK–DIQUARK SYSTEMATICS OF BARYONS COMPOSED BY LIGHT QUARKS q = u, d". International Journal of Modern Physics A 25, n.º 15 (20 de junho de 2010): 2965–95. http://dx.doi.org/10.1142/s0217751x10049050.

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Supposing quark–diquark structure of baryons, we look for systematics of baryons composed of light quarks (q = u, d). We systematize baryons using the notion of two diquarks: (i) axial–vector state, [Formula: see text], with the spin SD = 1 and isospin ID = 1 and (ii) scalar one, [Formula: see text], with the spin SD = 0 and isospin ID = 0. We consider several schemes for the composed baryons: (1) with different diquark masses, [Formula: see text], (2) with [Formula: see text] and overlapping [Formula: see text] and [Formula: see text] states (resonances), (3) with/without SU(6) constraints for low-lying states (with quark–diquark orbital momenta L = 0). In the high-mass region, the model predicts several baryon resonances at M ~ 2.0–2.9 GeV . Moreover, the model gives us the double pole structure (i.e. two poles with the same Re M but different Im M) in many amplitudes at masses M ≳ 2.0 GeV . We see also that for description of low-lying baryons (with L = 0), the SU(6) constraint is needed.

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NAWA, KANABU, HIDEO SUGANUMA e TORU KOJO. "BARYONS WITH HOLOGRAPHY". Modern Physics Letters A 23, n.º 27n30 (30 de setembro de 2008): 2364–67. http://dx.doi.org/10.1142/s0217732308029393.

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We perform the first study of baryons in holographic QCD with [Formula: see text] multi-D-brane system in type IIA superstring theory. The baryon is described as a chiral soliton solution in the four-dimensional meson effective action derived from holographic QCD. We also present a brief review of the holographic model from the viewpoints of recent hadron physics and QCD phenomenologies.

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Shah, Zalak Urjit, Amee Kakadiya, Keval Kumar Gandhi e Ajay Kumar Rai. "Properties of Doubly Heavy Baryons". Universe 7, n.º 9 (9 de setembro de 2021): 337. http://dx.doi.org/10.3390/universe7090337.

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We revisited the mass spectra of the Ξcc++ baryon with positive and negative parity states using Hypercentral Constituent Quark Model Scheme with Coloumb plus screened potential. The ground state of the baryon has been determined by the LHCb experiment, and the anticipated excited state masses of the baryon have been compared with several theoretical methodologies. The transition magnetic moments of all heavy baryons Ξcc++, Ξcc+, Ωcc+, Ξbb0, Ξbb−, Ωbb−, Ξbc+, Ξbc0, Ωbc0 are also calculated and their values are −1.013 μN, 1.048 μN, 0.961 μN, −1.69 μN, 0.73 μN, 0.48 μN, −1.39 μN, 0.94 μN and 0.710 μN, respectively.

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Gutsche, Thomas, Mikhail Ivanov, Jürgen Körner e Valery Lyubovitskij. "Novel Ideas in Nonleptonic Decays of Double Heavy Baryons". Particles 2, n.º 2 (13 de junho de 2019): 339–56. http://dx.doi.org/10.3390/particles2020021.

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The recent discovery of double charm baryon states by the LHCb Collaborarion and their high precision mass determination calls for a comprehensive analysis of the nonleptonic decays of double and single heavy baryons. Nonleptonic baryon decays play an important role in particle phenomenology since they allow for studying the interplay of long and short distance dynamics of the Standard Model (SM). Furthermore, they allow one to search for New Physics effects beyond the SM. We review recent progress in experimental and theoretical studies of the nonleptonic decays of heavy baryons with a focus on double charm baryon states and their decays. In particular, we discuss new ideas proposed by the present authors to calculate the W-exchange matrix elements of the nonleptonic decays of double heavy baryons. An important ingredient in our approach is the compositeness condition of Salam and Weinberg, and an effective implementation of infrared confinement both of which allow one to describe the nonperturbative structure of baryons composed of light and heavy quarks. Furthermore, we discuss an ab initio calculational method for the treatment of the so-called W-exchange diagrams generated by W ± boson exchange between quarks. We found that the W ± -exchange contributions are not suppressed in comparison with the tree-level (factorizing) diagrams and must be taken into account in the evaluation of matrix elements. Moreover, there are decay processes such as the doubly Cabibbo-suppressed decay Ξ c + → p ϕ recently observed by the LHCb Collaboration, which is contributed to only by one single W-exchange diagram.

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Chan, Man Ho. "Analytic expressions for the dark matter-baryon relations". International Journal of Modern Physics D 26, n.º 10 (20 de agosto de 2017): 1750118. http://dx.doi.org/10.1142/s0218271817501188.

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Recently, some very strong correlations between the distribution of dark matter and baryons (the dark matter-baryon relations) in galaxies with very different morphologies, masses, sizes and gas fractions have been obtained. Some models have been suggested to explain why the dark matter contribution is fully specified by that of the baryons. In this paper, we derive two analytic expressions to explain the observed dark matter-baryon relations based on the cold dark matter (CDM) model. The resultant expressions give excellent agreement with the observational data. The parameters involved in the analytic expressions are closely related to the amount of the baryon content. This model can provide a theoretical understanding of the strong correlations observed. We suggest that the observed relation represents the end product of galaxy formation.

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GERASYUTA, S. M., e E. E. MATSKEVICH. "CHARMED (70, 1-) BARYON MULTIPLET". International Journal of Modern Physics E 17, n.º 04 (abril de 2008): 585–610. http://dx.doi.org/10.1142/s0218301308010027.

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The masses of negative parity (70, 1-) charmed nonstrange baryons are calculated in the relativistic quark model. The relativistic three-quark equations of the (70, 1-) charmed baryon multiplet are found in the framework of the dispersion relation technique. The approximate solutions of these equations using the method based on the extraction of leading singularities of the amplitude are obtained. The calculated mass values of the (70, 1-) charmed baryons are in good agreement with the experimental data.

41

Cahill, RT, CD Roberts e J. Praschifka. "Baryon Structure and QCD". Australian Journal of Physics 42, n.º 2 (1989): 129. http://dx.doi.org/10.1071/ph890129.

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From QCD we derive a three-body Faddeev-type formulation of baryons, as qqq colour-singlet states bound by gluon exchange, which is covariant, has dynamically hidden chiral symmetry and incorporates the colour dynamics. The formulation exploits the dynamical role of colour "3 diquark substructure in baryons to simplify computations. For non-zero current quark masses the jP = ~ + and ~ - baryon octet mass formulae are shown to satisfy the Gell-Mann-Okubo and the Coleman-Glashow multiplet mass relationships.

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Dobrigkeit Chinellato, David. "Charm and multi-charm baryon measurements via strangeness tracking with the upgraded ALICE detector". EPJ Web of Conferences 259 (2022): 09004. http://dx.doi.org/10.1051/epjconf/202225909004.

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We present a new method for detection of multiply charmed baryons via their decays into strange baryons, using ‘strangeness tracking’. This method makes use of the state-of-the-art upgraded silicon detectors in ALICE during Runs 3, 4 and beyond will enable the novel possibility of tracking strange hadrons directly before they decay, leading to a very significant improvement in impactparameter resolution. In this work, we will discuss how this new technique will be crucial to distinguish secondary strange baryons originating from charm decays from primary strange baryons. This is a particularly interesting possibility for the Ω− baryon coming from Ωc0 → Ω−π+ decays, since there is no other relevant feeddown source for Ω−. This, in turn, means that the main Ω− background for the Ωc measurement will point most accurately to the primary vertex, unlike pions or protons from other charm baryon decays. We will illustrate the achievable performance of strangeness tracking for the Run 3 configuration of ALICE with the upgraded Inner Tracking System, which is fully instrumented with silicon pixel detectors. Moreover, we will discuss the potential of this technique in a future experiment with an extensive silicon tracking detector with a first layer very close to the interaction point. Finally, we will also cover other potential major applications of strangeness tracking, including measurements of hypernuclei such as the Λ3H.

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Kiren, O. V., Arun Kenath e Chandra Sivaram. "Primordial Planets with an Admixture of Dark Matter Particles and Baryonic Matter". Universe 9, n.º 9 (31 de agosto de 2023): 401. http://dx.doi.org/10.3390/universe9090401.

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It has been suggested that primordial planets could have formed in the early universe and the missing baryons in the universe could be explained by primordial free-floating planets of solid hydrogen. Many such planets were recently discovered around the old and metal-poor stars, and such planets could have formed in early epochs. Another possibility for missing baryons in the universe could be that these baryons are admixed with DM particles inside the primordial planets. Here, we discuss the possibility of the admixture of baryons in the DM primordial planets discussed earlier. We consider gravitationally bound DM objects with the DM particles constituting them varying in mass from 20 to100 GeV. Different fractions of DM particles mixed with baryonic matter in forming the primordial planets are discussed. For the different mass range of DM particles forming DM planets, we have estimated the radius and density of these planets with different fractions of DM and baryonic particles. It is found that for heavier-mass DM particles with the admixture of certain fractions of baryonic particles, the mass of the planet increases and can reach or even substantially exceed Jupiter mass. The energy released during the process of merger of such primordial planets is discussed. The energy required for the tidal breakup of such an object in the vicinity of a black hole is also discussed.

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Niedziela, Jeremi. "Studying the strong interaction with baryon-(anti)baryon femtoscopy in Pb-Pb collisions measured by ALICE". EPJ Web of Conferences 177 (2018): 04008. http://dx.doi.org/10.1051/epjconf/201817704008.

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The shape of the baryon-(anti)baryon femtoscopic correlation function is influenced by the size of the emission source, strong and Coulomb interactions and Quantum Statistics. Another factor introducing additional correlation structures is related to the residual correlations, which are related to the fact that baryons may come from decays of heavier particles. The correlation function of a given pair of baryons (for example pp) is closely connected with correlation functions of other particles (such as pΛ). Analysing correlation functions of multiple baryon pairs simultaneously can further constrain measured strong scattering parameters. A newly developed fitting procedure allowing for a combined fit of several correlation functions is presented. The procedure was applied to 2.76 TeV and 5.02 TeV Pb-Pb data measured by ALICE. The analysis was performed for all combinations of (anti)protons and (anti)lambdas for different collision centralities. Measured strong interaction parameters for pΛ, ΛΛ and heavier baryon-antibaryon (bb) pairs are shown and possible underlying physical processes are discussed.

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TSUGE, MASAYASU, TOSHIYUKI MORII e JUN-YA MORISHITA. "BARYON SPECTRUM IN THE POTENTIAL MODEL WITH RELATIVISTIC CORRECTIONS". Modern Physics Letters A 01, n.º 02 (maio de 1986): 131–39. http://dx.doi.org/10.1142/s0217732386000191.

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Relativistic corrections including the central forces (up to 1/m2) are calculated numerically for baryon systems. The χ2 analyses suggest the 2-body confining potential in the baryons to be predominantly of vector nature. Baryon masses with heavy flavor (c, b) are predicted and reproduced well.

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WEIGEL, HERBERT. "BARYONS AS THREE-FLAVOR SOLITONS". International Journal of Modern Physics A 11, n.º 14 (10 de junho de 1996): 2419–544. http://dx.doi.org/10.1142/s0217751x96001218.

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The description of baryons as soliton solutions of effective meson theories for three-flavor (up, down and strange) degrees of freedom is reviewed and the phenomenological implications are illuminated. In the collective approach the soliton configuration is equipped with baryon quantum numbers by canonical quantization of the coordinates describing the flavor orientation. The baryon spectrum resulting from exact diagonalization of the collective Hamiltonian is discussed. The prediction of static properties, such as the baryon magnetic moments and the Cabibbo matrix elements for semileptonic hyperon decays, are explored with regard to the influence of flavor symmetry breaking. In particular, the role of strange degrees of freedom in the nucleon is investigated for both the vector and axial vector current matrix elements. The latter are discussed extensively within the context of the proton spin puzzle. The influence of flavor symmetry breaking on the shape of the soliton is examined, and observed to cause significant deviations from flavor-covariant predictions on the baryon magnetic moments. Short range effects are incorporated by a chirally invariant inclusion of vector meson fields. These extensions are necessary for properly describing the singlet axial vector current and the neutron–proton mass difference. The effects of the vector meson excitations on baryon properties are also considered. The bound state description of hyperons and its generalization to baryons containing a heavy quark are illustrated. In the case of the Skyrme model a comparison is made between the collective quantization scheme and the bound state approach. Finally, the Nambu–Jona-Lasinio model is employed to demonstrate that hyperons can be described as solitons in a microscopic theory of the quark flavor dynamics. This is explained for both the collective and the bound state approaches to strangeness.

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COHEN, THOMAS D. "CHIRAL SYMMETRY AND HOLOGRAPHIC MODELS OF THE BARYON: TESTING HOLOGRAPHIC MODELS OF THE BARYON WITH MODEL-INDEPENDENT RELATIONS". International Journal of Modern Physics A 25, n.º 02n03 (30 de janeiro de 2010): 464–69. http://dx.doi.org/10.1142/s0217751x10048767.

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A model-independent relation for the long-distance behavior of baryon form factors in the large Nc and chiral limits is introduced and used to probe the consistency of various models of the baryon including recently proposed holographic models. This relation is satisfied by the Skyrme model and all other 4D semiclassical chiral soliton models. The "bottom-up" Pomarol-Wulzer holographic model which treats baryons as 5D Skyrmions also satisfies the relation. However, the "top down" holographic model treating baryons as instantons in the Sakai-Sugimoto model fails to satisfy the relation. This failure can ultimately be traced to the imposition of a scale separation in the model between the curvature scale and the KK scale; such a scale separation has no counterpart in QCD.

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IAZZI, F., R. INTROZZI, A. LAVAGNO, D. PIGATO e M. H. YOUNIS. "STRANGENESS PRODUCTION AT FINITE TEMPERATURE AND BARYON DENSITY IN AN EFFECTIVE RELATIVISTIC MEAN FIELD MODEL". International Journal of Modern Physics E 21, n.º 03 (março de 2012): 1250028. http://dx.doi.org/10.1142/s0218301312500280.

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We study the strangeness production in hot and dense nuclear medium, by requiring the conservation of the baryon density, electric charge fraction and zero net strangeness. The hadronic equation of state is investigated by means of an effective relativistic mean field model, with the inclusion of the full octet of baryons and kaon mesons. Kaons are considered taking into account of an effective chemical potential depending on the self-consistent interaction between baryons. The obtained results are compared with a minimal coupling scheme, calculated for different values of the anti-kaon optical potential and with noninteracting kaon particles. In this context, we also consider the possible onset of the kaon condensation for a wide range of temperatures and baryon densities.

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Courteau, Stéphane. "The Distribution of Mass in (Disk) Galaxies: Maximal or Not?" Proceedings of the International Astronomical Union 10, S309 (julho de 2014): 364–70. http://dx.doi.org/10.1017/s1743921314010540.

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AbstractThe relative distribution of matter in galaxies ought to be one of the most definitive predictions of galaxy formation models yet its validation is challenged by numerous observational, theoretical, and operational challenges. All galaxies are believed to be dominated by an invisible matter component in their outskirts. A debate has however been blazing for the last two decades regarding the relative fraction of baryons and dark matter in the inner parts of galaxies: whether galaxies are centrally dominated by baryons (“maximal disk”) is of issue. Some of those debates have been misconstrued on account of operational confusion, such as dark matter fractions being measured and compared at different radii. All galaxies are typically baryon-dominated (maximal) at the center and dark-matter dominated (sub-maximal) in their outskirts; for low-mass galaxies (Vtot ≲ 200 km s− 1), the mass of the dark halo equals the stellar mass at least within 2 disk scale lengths, the transition occurs at larger effective radii for more massive galaxies. An ultimate goal for galaxy structure studies is to achieve accurate data-model comparisons for the relative fractions of baryonic to total matter at any radius.

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QING-WU, WANG, e ZHANG PENG-MING. "CHARMED BARYON IN A STRING MODEL". International Journal of Modern Physics E 19, n.º 01 (janeiro de 2010): 113–22. http://dx.doi.org/10.1142/s0218301310014674.

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Charmed baryon spectroscopy has been studied under a string model. In this model, charmed baryons are composed of a diquark and a charm quark which are connected by a constant tension. In this diquark picture, the quantum numbers JP of confirmed baryons have been well assigned. Energies of the first and second orbital excitations have been predicted and compared with the experimental data. Meanwhile, diquark masses have been extracted in the background of charm quark which satisfy a splitting relation based on spin–spin interaction.