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Articoli di riviste sul tema "Neutron dark decay"

Autore: Grafiati

Pubblicato: 7 dicembre 2024

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1

Fornal, Bartosz. "Neutron Dark Decay". Universe 9, n. 10 (16 ottobre 2023): 449. http://dx.doi.org/10.3390/universe9100449.

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Abstract (sommario):

There exists a puzzling disagreement between the results for the neutron lifetime obtained in experiments using the beam technique versus those relying on the bottle method. A possible explanation of this discrepancy postulates the existence of a beyond-Standard-Model decay channel of the neutron involving new particles in the final state, some of which can be dark matter candidates. We review the current theoretical status of this proposal and discuss the particle physics models accommodating such a dark decay. We then elaborate on the efforts undertaken to test this hypothesis, summarizing the prospects for probing neutron dark decay channels in future experiments.

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2

Sun, X., E. Adamek, B. Allgeier, M. Blatnik, T. J. Bowles, L. J. Broussard, M. A. P. Brown et al. "Search for neutron dark decay: n → χ + e+e−". EPJ Web of Conferences 219 (2019): 05008. http://dx.doi.org/10.1051/epjconf/201921905008.

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In January, 2018, Fornal and Grinstein proposed that a previously unobserved neutron decay branch to a dark matter particle (χ) could account for the discrepancy in the neutron lifetime observed in two different types of experiments. One of the possible final states discussed includes a single χ along with an e+e− pair. We use data from the UCNA (Ultracold Neutron Asymmetry) experiment to set limits on this decay channel. Coincident electron-like events are detected with ∼ 4π acceptance using a pair of detectors that observe a volume of stored Ultracold Neutrons (UCNs). We use the timing information of coincidence events to select candidate dark sector particle decays by applying a timing calibration and selecting events within a physically-forbidden timing region for conventional n → p + e- + ν̅e decays. The summed kinetic energy (Ee+e−) from such events is reconstructed and used to set limits, as a function of the χ mass, on the branching fraction for this decay channel.

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3

Zhou, Dake. "Neutron Star Constraints on Neutron Dark Decays". Universe 9, n. 11 (17 novembre 2023): 484. http://dx.doi.org/10.3390/universe9110484.

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Motivated by the neutron lifetime puzzle, it is proposed that neutrons may decay into new states yet to be observed. We review the neutron star constraints on dark fermions carrying unit baryon number with masses around 939 MeV, and discuss the interaction strengths required for the new particle. The possibility of neutrons decaying into three dark fermions is investigated. While up to six flavors of dark quarks with masses around 313 MeV can be compatible with massive pulsars, any such exotic states lighter than about 270 MeV are excluded by the existence of low-mass neutron stars around ∼1.2M⊙. Light dark quarks in the allowed mass range may form a halo surrounding normal neutron stars. We discuss the potential observable signatures of the halo during binary neutron star mergers.

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4

Beck, D. H. "Neutron decay, dark matter and neutron stars". EPJ Web of Conferences 219 (2019): 05006. http://dx.doi.org/10.1051/epjconf/201921905006.

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Following up on a suggestion that decay to a dark matter fermion might explain the 4σ discrepancy in the neutron lifetime, we consider the implications of such a fermion on neutron star structure. We find that including it reduces the maximum neutron star mass to well below the observed masses. In order to recover stars with the observed masses, the (repulsive) self-interactions of the dark fermion would have to be stronger than those of the nucleon-nucleon interaction.

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5

Motta, T. F., P. A. M. Guichon e A. W. Thomas. "Neutron to dark matter decay in neutron stars". International Journal of Modern Physics A 33, n. 31 (10 novembre 2018): 1844020. http://dx.doi.org/10.1142/s0217751x18440207.

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Recent proposals have suggested that a previously unknown decay mode of the neutron into a dark matter particle could solve the long lasting measurement problem of the neutron decay width. We show that, if the dark particle in neutron decay is the major component of the dark matter in the universe, this proposal is in disagreement with modern astrophysical data concerning neutron star masses.

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6

Husain, Wasif, Theo F. Motta e Anthony W. Thomas. "Consequences of neutron decay inside neutron stars". Journal of Cosmology and Astroparticle Physics 2022, n. 10 (1 ottobre 2022): 028. http://dx.doi.org/10.1088/1475-7516/2022/10/028.

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Abstract The hypothesis that neutrons might decay into dark matter is explored using neutron stars as a testing ground. It is found that in order to obtain stars with masses at the upper end of those observed, the dark matter must experience a relatively strong self-interaction. Conservation of baryon number and energy then require that the star must undergo some heating, with a decrease in radius, leading to an increase in speed of rotation over a period of days.

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7

Wietfeldt, Fred E. "The Neutron Lifetime Discrepancy and Its Implications for Cosmology and Dark Matter". Symmetry 16, n. 8 (26 luglio 2024): 956. http://dx.doi.org/10.3390/sym16080956.

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Free neutron decay is the prototype for nuclear beta decay and other semileptonic weak particle decays. It provides important insights into the symmetries of the weak nuclear force. Neutron decay is important for understanding the formation and abundance of light elements in the early universe. The two main experimental approaches for measuring the neutron lifetime, the beam method and the ultracold neutron storage method, have produced results that currently differ by 9.8 ± 2.0 s. While this discrepancy probably has an experimental origin, a more exciting prospect is that it may be explained by new physics, with possible connections to dark matter. The experimental status of the neutron lifetime is briefly reviewed, with an emphasis on its implications for cosmology, astrophysics, and dark matter.

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8

Husain, Wasif, Dipan Sengupta e A. W. Thomas. "Constraining Dark Boson Decay Using Neutron Stars". Universe 9, n. 7 (26 giugno 2023): 307. http://dx.doi.org/10.3390/universe9070307.

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Abstract (sommario):

Inspired by the well-known anomaly in the lifetime of the neutron, we investigated its consequences inside neutron stars. We first assessed the viability of the neutron decay hypothesis suggested by Fornal and Grinstein within neutron stars, in terms of the equation of state and compatibility with observed properties. This was followed by an investigation of the constraint information on neutron star cooling that can be placed on the decay rate of the dark boson into standard model particles, in the context of various BSM ideas.

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9

Fornal, Bartosz, e Benjamín Grinstein. "Dark side of the neutron?" EPJ Web of Conferences 219 (2019): 05005. http://dx.doi.org/10.1051/epjconf/201921905005.

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We discuss our recently proposed interpretation of the discrepancy between the bottle and beam neutron lifetime experiments as a sign of a dark sector. The difference between the outcomes of the two types of measurements is explained by the existence of a neutron dark decay channel with a branching fraction 1%. Phenomenologically consistent particle physics models for the neutron dark decay can be constructed and they involve a strongly self-interacting dark sector. We elaborate on the theoretical developments around this idea and describe the efforts undertaken to verify it experimentally.

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10

Karananas, Georgios K., e Alexis Kassiteridis. "Small-scale structure from neutron dark decay". Journal of Cosmology and Astroparticle Physics 2018, n. 09 (24 settembre 2018): 036. http://dx.doi.org/10.1088/1475-7516/2018/09/036.

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11

Fornal, Bartosz, e Benjamín Grinstein. "Neutron’s dark secret". Modern Physics Letters A 35, n. 31 (21 agosto 2020): 2030019. http://dx.doi.org/10.1142/s0217732320300190.

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Abstract (sommario):

The existing discrepancy between neutron lifetime measurements in bottle and beam experiments has been interpreted as a sign of the neutron decaying to dark particles. We summarize the current status of this proposal, including a discussion of particle physics models involving such a portal between the Standard Model and a baryonic dark sector. We also review further theoretical developments around this idea and elaborate on the prospects for verifying the neutron dark decay hypothesis in current and upcoming experiments.

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12

Ivanov, Andrey N., Roman Höllwieser, Nataliya I. Troitskaya, Markus Wellenzohn e Yaroslav A. Berdnikov. "Electrodisintegration of Deuteron into Dark Matter and Proton Close to Threshold". Symmetry 13, n. 11 (12 novembre 2021): 2169. http://dx.doi.org/10.3390/sym13112169.

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We discuss an investigation of the dark matter decay modes of the neutron, proposed by Fornal and Grinstein (2018–2020), Berezhiani (2017, 2018) and Ivanov et al. (2018) for solution of the neutron lifetime anomaly problem, through the analysis of the electrodisintegration of the deuteron d into dark matter fermions χ and protons p close to threshold. We calculate the triple-differential cross section for the reaction e−+d→χ+p+e− and propose to search for such a dark matter channel in coincidence experiments on the electrodisintegration of the deuteron e−+d→n+p+e− into neutrons n and protons close to threshold with outgoing electrons, protons, and neutrons in coincidence. An absence of neutron signals should testify to a detection of dark matter fermions.

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13

Fornal, Bartosz, e Benjamin Grinstein. "Dark particle interpretation of the neutron decay anomaly". Journal of Physics: Conference Series 1308 (agosto 2019): 012010. http://dx.doi.org/10.1088/1742-6596/1308/1/012010.

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14

Shirke, Swarnim, Suprovo Ghosh, Debarati Chatterjee, Laura Sagunski e Jürgen Schaffner-Bielich. "R-modes as a new probe of dark matter in neutron stars". Journal of Cosmology and Astroparticle Physics 2023, n. 12 (1 dicembre 2023): 008. http://dx.doi.org/10.1088/1475-7516/2023/12/008.

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Abstract In this work, we perform the first systematic investigation of effects of the presence of dark matter on r-mode oscillations in neutron stars (NSs). Using a self-interacting dark matter (DM) model based on the neutron decay anomaly and a hadronic model obtained from the posterior distribution of a recent Bayesian analysis, we impose constraints on the DM self-interaction strength using recent multimessenger astrophysical observations. We also put new constraints on the DM fraction for this model of DM. The constrained DM interaction strength is then used to estimate DM self-interaction cross section and shear viscosity resulting from DM, which is found to be several orders of magnitude smaller than shear viscosity due to hadronic matter. Assuming chemical equilibrium among DM fermions and neutrons, we estimate the bulk viscosity resulting from the dark decay of neutrons considering different scenarios for the temperature dependence of the reaction rate and investigate the effect on the r-mode instability window. We conclude that DM shear and bulk viscosity may significantly modify the r-mode instability window compared with the minimal hadronic viscosities, depending on the temperature dependence of the process. We also found that for the window to be compatible with the X-ray and pulsar observational data, the rate for the dark decay process must be fast.

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15

Bianchi, Abele, e Giovanni Guido. "From the Dark Neutron to the Neutron Decay Anomaly and Lithium Cosmologic Problem". Journal of High Energy Physics, Gravitation and Cosmology 08, n. 03 (2022): 494–516. http://dx.doi.org/10.4236/jhepgc.2022.83036.

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16

Dymnikova, Irina, e Maxim Khlopov. "Regular black hole remnants and graviatoms with de Sitter interior as heavy dark matter candidates probing inhomogeneity of early universe". International Journal of Modern Physics D 24, n. 13 (novembre 2015): 1545002. http://dx.doi.org/10.1142/s0218271815450029.

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Abstract (sommario):

We address the question of regular primordial black holes with de Sitter interior, their remnants and gravitational vacuum solitons G-lumps as heavy dark matter candidates providing signatures for inhomogeneity of early universe, which is severely constrained by the condition that the contribution of these objects in the modern density does not exceed the total density of dark matter. Primordial black holes and their remnants seem to be most elusive among dark matter candidates. However, we reveal a nontrivial property of compact objects with de Sitter interior to induce proton decay or decay of neutrons in neutron stars. The point is that they can form graviatoms, binding electrically charged particles. Their observational signatures as dark matter candidates provide also signatures for inhomogeneity of the early universe. In graviatoms, the cross-section of the induced proton decay is strongly enhanced, what provides the possibility of their experimental searches. We predict proton decay paths induced by graviatoms in the matter as an observational signature for heavy dark matter searches at the IceCUBE experiment.

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17

Märkisch, B., H. Abele, D. Dubbers, H. Saul e T. Soldner. "Accurate Measurement of the Beta-Asymmetry in Neutron Decay Rules out Dark Decay Mode". Journal of Surface Investigation: X-ray, Synchrotron and Neutron Techniques 14, S1 (ottobre 2020): S140—S143. http://dx.doi.org/10.1134/s1027451020070319.

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18

Klopf, Michael, Erwin Jericha, Bastian Märkisch, Heiko Saul, Torsten Soldner e Hartmut Abele. "Dark decay channel analysis (n → χ + e+ e−) with the PERKEO II experiment". EPJ Web of Conferences 219 (2019): 05007. http://dx.doi.org/10.1051/epjconf/201921905007.

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Abstract (sommario):

Discrepancies from beam and bottle type experiments measuring the neutron lifetime are on the 4σ level. In recent publications Fornal and Grinstein proposed that the puzzle could be solved if the neutron would decay on the one percent level via a dark decay mode [1], one possible branch being n → χ + e+e−. With data from the Perkeo II experiment we set limits on the branching fraction and exclude a one percent contribution for 96% of the allowed mass range for the dark matter particle. With this publication, we give a detailed description of the experiment and some selected details of the analysis.

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19

Terol-Calvo, Jorge. "Supernova Constraints on Dark Flavored Sectors". Journal of Physics: Conference Series 2156, n. 1 (1 dicembre 2021): 012056. http://dx.doi.org/10.1088/1742-6596/2156/1/012056.

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Abstract Proto-neutron stars forming a few seconds after core-collapse supernovae are hot and dense environments where hyperons can be efficiently produced by weak processes. By making use of various state-of-the-art supernova simulations combined with the proper extensions of the equations of state including Λ hyperons, we calculate the cooling of the star induced by the emission of dark particles X0 through the decay Λ → nX 0. Comparing this novel energy-loss process to the neutrino cooling of SN 1987A allows us to set a stringent upper limit on the branching fraction, BR(Λ → nX 0) ≤ 8 × 10−9, that we apply to massless dark photons and axions with flavor-violating couplings to quarks. We find that the new supernova bound can be orders of magnitude stronger than other limits in dark-sector models.

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20

Vergados, J. D. "Searching for light WIMPS in view of neutron decay to dark matter". Journal of Physics G: Nuclear and Particle Physics 46, n. 10 (21 agosto 2019): 105002. http://dx.doi.org/10.1088/1361-6471/ab326d.

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21

Berezhiani, Zurab. "Matter, dark matter, and antimatter in our Universe". International Journal of Modern Physics A 33, n. 31 (10 novembre 2018): 1844034. http://dx.doi.org/10.1142/s0217751x18440347.

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Abstract (sommario):

I discuss the possibility of dark matter conversion into our antimatter, assuming that a part of dark matter is represented by a hypothetical mirror matter. In the Early Universe, [Formula: see text] and [Formula: see text] violating interactions between the particles of ordinary and mirror worlds can co-generate their baryon asymmetries in comparable amounts, [Formula: see text], also predicting the sign of mirror baryon asymmetry. At low energies, the same interactions induce particle mixing phenomena between two sectors. In this way, e.g. mirror neutron [Formula: see text] should oscillate into our antineutron [Formula: see text], with probability that depends on environmental conditions as matter density and magnetic fields. This oscillation can be faster than the neutron decay itself, with [Formula: see text] conversion rate accessible for the experimental search. It can have fascinating phenomenological and astrophysical consequences, and can potentially open an unlimited source of energy by transforming dark mirror matter into antimatter in a controllable way.

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22

Solmaz, M., M. Balzer, K. Eitel, A. Ferella, U. Oberlack, U. Pirling, F. Pompa, D. Tcherniakhovski, K. Valerius e S. Wüstling. "Design of a mobile neutron spectrometer for the Laboratori Nazionali del Gran Sasso (LNGS)". Journal of Instrumentation 18, n. 10 (1 ottobre 2023): P10022. http://dx.doi.org/10.1088/1748-0221/18/10/p10022.

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Abstract Environmental neutrons are a source of background for rare event searches (e.g., dark matter direct detection and neutrinoless double beta decay experiments) taking place in deep underground laboratories. The overwhelming majority of these neutrons are produced in the cavern walls by means of intrinsic radioactivity of the rock and concrete. Their flux and spectrum depend on time and location. Precise knowledge of this background is necessary to devise sufficient shielding and veto mechanisms, improving the sensitivity of the neutron-susceptible underground experiments. In this report, we present the design and the expected performance of a mobile neutron detector for the LNGS underground laboratory. The detector is based on capture-gated spectroscopy technique and comprises essentially a stack of plastic scintillator bars wrapped with gadolinium foils. The extensive simulation studies demonstrate that the detector will be capable of measuring ambient neutrons at low flux levels (∼10-6 n/cm2/s) at LNGS, where the ambient gamma flux is by about 5 orders of magnitude larger.

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23

Serebrov A. P., Lyamkin V. A., Fomin A. K. e Onegin M. S. "Superfluid helium based ultracold neutron source for the PIK reactor". Technical Physics 92, n. 6 (2022): 763. http://dx.doi.org/10.21883/tp.2022.06.54425.21-22.

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The PIK reactor at NRC "Kurchatov Institute"-PNPI is going to be equipped with a high-flux Ultra Cold Neutron (UCN) source for fundamental physics researches. The UCN source will use superfluid helium, which will make possible to achieve the density of UCN 2.2·10^3 cm-3, that has not yet been achieved anywhere in the world. The UCN source will be installed on the GEK-4 channel, which will make possible to obtain a low value of heat influx to cryogenic vessels from reactor radiation. The heat removal from the UCN source vessel will be implemented by using a heat exchanger. The calculated UCN density in the EDM spectrometer chamber at the PIK is going to be 200 cm-3, which is 20 times higher than the existing UCN densities in the world. For a new UCN source based on superfluid helium, an extensive research program has been developed in field of the physics of fundamental interactions, including the search for a nonzero neutron EDM, precision measurement of the neutron lifetime, and search for mirror dark matter. Keywords: ultracold neutrons, neutron sources, superfluid helium, neutron EDM, neutron decay.

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24

McKeen, David, e Maxim Pospelov. "How Long Does the Hydrogen Atom Live?" Universe 9, n. 11 (4 novembre 2023): 473. http://dx.doi.org/10.3390/universe9110473.

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It is possible that the proton is stable while atomic hydrogen is not. This is the case in models with new particles carrying baryon number which are light enough to be stable themselves, but heavy enough so that proton decay is kinematically blocked. Models of new physics that explain the neutron lifetime anomaly generically have this feature, allowing for atomic hydrogen to decay through electron capture on a proton. We calculate the radiative hydrogen decay rate involving the emission of a few hundred keV photon, which makes this process experimentally detectable. In particular, we show that the low energy part of the Borexino spectrum is sensitive to radiative hydrogen decay, and turn this into a limit on the hydrogen lifetime of order 1030s or stronger. For models where the neutron mixes with a dark baryon, χ, this limits the mixing angle to roughly 10−11, restricting the n→χγ branching to 10−4, over a wide range of parameter space.

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25

Gimsa, Andreas. "Calculation of the Neutrino Mass". International Journal of Scientific Research and Management 8, n. 05 (12 maggio 2020): 13–19. http://dx.doi.org/10.18535/ijsrm/v8i05.aa01.

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The determination of the neutrino mass is considered an important milestone in physics and especially in cosmology. Because it is so extraordinarily small, the usual methods for determining the mass of elementary particles fail. After Wolfgang Pauli's prediction of the neutrino in 1930, experimental proof was not possible until 1956, when an electron antineutrino met a proton and produced a positron and a neutron. The Karlsruhe Tritium Neutrino Experiment KATRIN [1.] is intended to determine the neutrino mass with unique accuracy or, if the sensitivity of the measuring technique is not yet sufficient, to further limit its upper limit. A theoretically exact determination of mass is not yet possible. The present publication is dedicated to this topic. Assuming a mass decay in the universe that includes the neutrino mass, a precise calculation method is proposed and subsequently justified. The effects of neutrino splitting from the proton are examined. In a cosmological perspective, further effects that neutrino decay could have on the expansion of space, gravity, dark mass, magnetic monopoles and time are investigated.

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26

AHLEN, S. P. "TIME-PROJECTION-CHAMBERS WITH OPTICAL READOUT FOR DARK MATTER, DOUBLE BETA DECAY, AND NEUTRON MEASUREMENTS". International Journal of Modern Physics A 25, n. 24 (30 settembre 2010): 4525–75. http://dx.doi.org/10.1142/s0217751x10050081.

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In recent years, there have been impressive advances in the technology of cameras using charged coupled devices (CCD's) and electron multiplying charged coupled devices (EMCCD's) that make possible a number of applications for the detection of ionizing radiation. The new cameras have quantum efficiencies exceeding 90%, effective noise levels less than one electron per pixel, and can be made to detect light ranging from the ultraviolet to the infrared. When combined with photomultiplier tubes (PMT's), and when used with Time-Projection-Chambers (TPC's) that contain narrow gap mesh charge amplification stages and scintillating gas compositions, these cameras can be used to provide three-dimensional images of particle tracks. There are many applications for such devices, including direction sensitive searches for dark matter, measurements of thermal and fast neutrons, and searches for double-beta-decay. I will describe the operation of optical TPC's and their various applications in this review article.

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27

Wu, Tong. "KL0→γ+darkphoton(γ¯) Search at the J-PARC KOTO Experiment". Journal of Physics: Conference Series 2446, n. 1 (1 febbraio 2023): 012054. http://dx.doi.org/10.1088/1742-6596/2446/1/012054.

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Abstract We present the study of massless dark photons in the decay of K L 0 → γ γ ¯ in the J-PARC KOTO experiment. The massless dark photon ( γ ¯ ) is different from the massive dark photon because it does not mix directly with ordinary photons, but it could interact with SM particles through direct coupling with quarks. In some theoretical predictions, the B R ( K L 0 → γ γ ¯ ) can be as large as 𝒪(10-3), which is well within the sensitivity of KOTO. Because of the lack of kinematic constraints, searching for K L 0 → γ γ ¯ could be challenging, but the hermetic veto system of KOTO provides a unique opportunity to probe for this decay. We used three techniques to suppress the neutron background, based on machine learning, Fourier analysis, and both-end readout. We will present the background suppression result based on data collected in 2020.

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28

Trzaska, W. H., T. Enqvist, K. Jedrzejczak, J. Joutsenvaara, M. Kasztelan, O. Kotavaara, P. Kuusiniemi et al. "DM-like anomalies in neutron multiplicity spectra". Journal of Physics: Conference Series 2156, n. 1 (1 dicembre 2021): 012029. http://dx.doi.org/10.1088/1742-6596/2156/1/012029.

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Abstract A new experiment collects data, since November 2019, at a depth of 210 m.w.e. in the Callio Lab in the Pyhasalmi mine in Finland. The setup, called NEMESIS (New Emma MEasurementS Including neutronS), incorporates infrastructure from the EMMA experiment with neutron and large-area plastic scintillator detectors. The experiment’s primary aim is to combine muon tracking with position-sensitive neutron detection to measure precision yields, multiplicities, and lateral distributions of high-multiplicity neutron events induced by cosmic muons in various materials. The data are relevant for background evaluation of the deep-underground searches for Dark Matter (DM), neutrino-less double beta decay, etc. Preliminary analysis revealed anomalies in muon-suppressed neutron multiplicity spectra collected during a 344-day run (live time) with a 565 kg Pb target. The spectra, otherwise well described by an exponential fit, show three peaks at high multiplicities. Although still at a low statistical significance, these small excesses match the outcome of an earlier measurement. The nature of the anomalies remains unclear, but, in principle, they may be a signature of self-annihilation of a WIMP with a mass close to 13 GeV/c2. With that assumption, the expected cross-section would be around 10−42 cm2 for Spin-Dependent or 10−46 cm2 for Spin Independent interactions. We propose verifying this hypothesis with an upgraded NEMESIS experiment, able to collect an order of magnitude more data than this measurement. Based on the statistical uncertainty, analysis of the event rate indicates that cross-section limits for DM mass range of approximately 3-40 GeV/c2 can be investigated with such a setup.

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29

Lewicka, Sylwia, e Jerzy Dryzek. "Positron Annihilation Characteristics in Superstrong Magnetic Fields". Materials Science Forum 666 (dicembre 2010): 31–34. http://dx.doi.org/10.4028/www.scientific.net/msf.666.31.

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The recent interest in positrons distribution in the space revealed the anomalous presence of high energetic positrons. There are different possible origins of such positrons, including the decay of heavy particles in the dark matter, also pulsars or neutron stars. In our study we calculated the annihilation properties of the electron – positron bound system in superstrong magnetic fields expected for neutron stars. For this aim we use solutions of the (relativistic) Bethe-Salpeter equation derived by L.B. Leinson and A. Perez [1]. The results indicate strong dependency of the annihilation properties (rate and intensity) on the value of the magnetic field.

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30

Jeong, Kwang Sik, Kohei Matsukawa, Shota Nakagawa e Fuminobu Takahashi. "Cosmological effects of Peccei-Quinn symmetry breaking on QCD axion dark matter". Journal of Cosmology and Astroparticle Physics 2022, n. 03 (1 marzo 2022): 026. http://dx.doi.org/10.1088/1475-7516/2022/03/026.

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Abstract We study cosmological effects of explicit Peccei-Quinn breaking on the QCD axion dark matter. We find that the axion abundance decreases or increases significantly depending on the initial position, even for a tiny Peccei-Quinn breaking that satisfies the experimental bound of the neutron electric dipole measurements. If the axion first starts to oscillate around a wrong vacuum and if it gets trapped there until the false vacuum disappears due to non-perturbative QCD effects, its abundance increases significantly and is independent of the decay constant fa , as first pointed out in ref. [1]. Thus, the axion produced by the trapping mechanism can explain dark matter even when the decay constant is close to the lower limit due to stellar cooling arguments. On the other hand, if the axion starts to oscillate about a potential minimum close to the low-energy vacuum, its abundance is significantly reduced because of the adiabatic suppression mechanism. This relaxes the upper limit of the axion window to large values of fa . We also discuss how the axionic isocurvature perturbation is affected by the Peccei-Quinn breaking term, and show that it can be suppressed in both regimes. In particular, the isocurvature bound on the inflation scale is relaxed by many orders of magnitudes for fa ≳ 1011 GeV compared to the conventional scenario.

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Lee, Billy K. K., Ming-chung Chu e Lap-Ming Lin. "Could the GW190814 Secondary Component Be a Bosonic Dark Matter Admixed Compact Star?" Astrophysical Journal 922, n. 2 (1 dicembre 2021): 242. http://dx.doi.org/10.3847/1538-4357/ac2735.

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Abstract We investigate whether the recently observed 2.6 M ⊙ compact object in the gravitational wave event GW190814 can be a bosonic dark matter (DM) admixed compact star. By considering the three constraints of mass, radius, and the stability of such an object, we find that if the DM is made of QCD axions, their particle mass m is constrained to a range that has already been ruled out by the independent constraint imposed by the stellar-mass black hole superradiance process. The 2.6 M ⊙ object can still be a neutron star admixed with at least 2.0 M ⊙ of DM made of axion-like particles (or even a pure axion-like particle star) if 2 × 10−11 eV ≤ m ≤ 2.4 × 10−11 eV (2.9 × 10−11 eV ≤ m ≤ 3.2 × 10−11 eV) with a decay constant of f ≥ 8 × 1017 GeV.

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32

Grayling, M., C. P. Gutiérrez, M. Sullivan, P. Wiseman, M. Vincenzi, S. González-Gaitán, B. E. Tucker et al. "Understanding the extreme luminosity of DES14X2fna". Monthly Notices of the Royal Astronomical Society 505, n. 3 (24 maggio 2021): 3950–67. http://dx.doi.org/10.1093/mnras/stab1478.

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ABSTRACT We present DES14X2fna, a high-luminosity, fast-declining Type IIb supernova (SN IIb) at redshift z = 0.0453, detected by the Dark Energy Survey (DES). DES14X2fna is an unusual member of its class, with a light curve showing a broad, luminous peak reaching Mr ≃ −19.3 mag 20 d after explosion. This object does not show a linear decline tail in the light curve until ≃60 d after explosion, after which it declines very rapidly (4.30 ± 0.10 mag 100 d−1 in the r band). By fitting semi-analytic models to the photometry of DES14X2fna, we find that its light curve cannot be explained by a standard 56Ni decay model as this is unable to fit the peak and fast tail decline observed. Inclusion of either interaction with surrounding circumstellar material or a rapidly-rotating neutron star (magnetar) significantly increases the quality of the model fit. We also investigate the possibility for an object similar to DES14X2fna to act as a contaminant in photometric samples of SNe Ia for cosmology, finding that a similar simulated object is misclassified by a recurrent neural network (RNN)-based photometric classifier as an SN Ia in ∼1.1–2.4 per cent of cases in DES, depending on the probability threshold used for a positive classification.

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33

Abusleme, Angel, Thomas Adam, Shakeel Ahmad, Rizwan Ahmed, Sebastiano Aiello, Muhammad Akram, Abid Aleem et al. "JUNO sensitivity to the annihilation of MeV dark matter in the galactic halo". Journal of Cosmology and Astroparticle Physics 2023, n. 09 (1 settembre 2023): 001. http://dx.doi.org/10.1088/1475-7516/2023/09/001.

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Abstract We discuss JUNO sensitivity to the annihilation of MeV dark matter in the galactic halo via detecting inverse beta decay reactions of electron anti-neutrinos resulting from the annihilation. We study possible backgrounds to the signature, including the reactor neutrinos, diffuse supernova neutrino background, charged- and neutral-current interactions of atmospheric neutrinos, backgrounds from muon-induced fast neutrons and cosmogenic isotopes. A fiducial volume cut, as well as the pulse shape discrimination and the muon veto are applied to suppress the above backgrounds. It is shown that JUNO sensitivity to the thermally averaged dark matter annihilation rate in 10 years of exposure would be significantly better than the present-day best limit set by Super-Kamiokande and would be comparable to that expected by Hyper-Kamiokande.

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34

Ivanov, A. N., R. Höllwieser, N. I. Troitskaya, M. Wellenzohn e Ya A. Berdnikov. "Neutron dark matter decays and correlation coefficients of neutron β−-decays". Nuclear Physics B 938 (gennaio 2019): 114–30. http://dx.doi.org/10.1016/j.nuclphysb.2018.11.005.

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35

Seto, Osamu, e Takashi Shimomura. "Underground detections of an extra gauge interacting sterile neutrino dark matter". Journal of Physics: Conference Series 2156, n. 1 (1 dicembre 2021): 012053. http://dx.doi.org/10.1088/1742-6596/2156/1/012053.

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Abstract (sommario):

Abstract We show that decay products from sterile neutrino dark matter in extra U(1) models are detectable in both direct dark matter detection experiments and neutrino telescope. The sterile neutrino dark matter interacts with a light gauge boson and decays into neutrinos. Those neutrinos could scatter off nuclei with a large enough recoil energy in direct dark matter detection experiments as WIMPs do.

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36

Naydenov, M. "Phenomenology of dark tensor currents". Journal of Physics: Conference Series 2668, n. 1 (1 dicembre 2023): 012003. http://dx.doi.org/10.1088/1742-6596/2668/1/012003.

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Abstract (sommario):

Abstract In this work we suggest a dark mediator model which extends the usual U(1) Lagrangian by including new degrees of freedom coupling to Standard Model fermions. Such dark particles can contribute to the neutral pion decay. For interaction constant and the dark particle mass consistent with the observed anomalies in the nuclear decays by the ATOMKI group we show that the dark tensor particles naturally incorporate lepton universality violation which introduces sizable effect on the muon anomalous magnetic moment.

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37

Biekert, A., C. Chang, L. Chaplinsky, C. W. Fink, W. D. Frey, M. Garcia-Sciveres, W. Guo et al. "A portable and monoenergetic 24 keV neutron source based on ¹²⁴Sb-⁹Be photoneutrons and an iron filter". Journal of Instrumentation 18, n. 07 (1 luglio 2023): P07018. http://dx.doi.org/10.1088/1748-0221/18/07/p07018.

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Abstract (sommario):

Abstract A portable monoenergetic 24 keV neutron source based on the 124Sb-9Be photoneutron reaction and an iron filter has been constructed and characterized. The coincidence of the neutron energy from SbBe and the low interaction cross-section with iron (mean free path up to 29 cm) makes pure iron specially suited to shield against gamma rays from 124Sb decays while letting through the neutrons. To increase the 124Sb activity and thus the neutron flux, a >1 GBq 124Sb source was produced by irradiating a natural Sb metal pellet with a high flux of thermal neutrons in a nuclear reactor. The design of the source shielding structure makes for easy transportation and deployment. A hydrogen gas proportional counter is used to characterize the neutrons emitted by the source and a NaI detector is used for gamma background characterization. At the exit opening of the neutron beam, the characterization determined the neutron flux in the energy range 20–25 keV to be 6.00±0.30 neutrons per cm2 per second and the total gamma flux to be 245±8 gammas per cm2 per second (numbers scaled to 1 GBq activity of the 124Sb source). A liquid scintillator detector is demonstrated to be sensitive to neutrons with incident kinetic energies from 8 to 17 keV, so it can be paired with the source as a backing detector for neutron scattering calibration experiments. This photoneutron source provides a good tool for in-situ low energy nuclear recoil calibration for dark matter experiments and coherent elastic neutrino-nucleus scattering experiments.

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38

Hannestad, Steen. "Decay-Produced Neutrino Hot Dark Matter". Physical Review Letters 80, n. 21 (25 maggio 1998): 4621–24. http://dx.doi.org/10.1103/physrevlett.80.4621.

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39

Covi, Laura, Michael Grefe, Alejandro Ibarra e David Tran. "Neutrino signals from dark matter decay". Journal of Cosmology and Astroparticle Physics 2010, n. 04 (19 aprile 2010): 017. http://dx.doi.org/10.1088/1475-7516/2010/04/017.

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40

KIM, HANG BAE. "SIGNALS FOR LIGHT DARK MATTER AXINO". Modern Physics Letters A 22, n. 25n28 (14 settembre 2007): 2113–20. http://dx.doi.org/10.1142/s0217732307025364.

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Abstract (sommario):

Light dark matter aims at explaining the 511 keV γ-ray line emission from the galactic bulge as well as cold dark matter in our universe. The former is achieved via the annihilations or decays of light dark matter particles, which implies interesting observational consequences in addition to 511 keV γ-rays. We consider the axino in the 1 ~ 10 MeV mass range as the light dark matter particle and discuss the particle physics models for it, its cosmological production, and its decay arising from R-parity violation. For additional observational signals, we consider the connection to the neutrino data made by bilinear R-parity violations and the continuum γ-ray emission from light dark matter particles.

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41

Lichkunov, Alexey, Konstantin Stankevich, Alexander Studenikin e Maxim Vyalkov. "Neutrino quantum decoherence engendered by neutrino decay to photons, familons and gravitons". Journal of Physics: Conference Series 2156, n. 1 (1 dicembre 2021): 012240. http://dx.doi.org/10.1088/1742-6596/2156/1/012240.

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Abstract (sommario):

Abstract We developed the previously proposed theoretical framework based on the quantum field theory of open systems applied to neutrinos. Within this framework we have considered the neutrino evolution and neutrino flavour oscillations taking into account for the decay of a heavier neutrino state to a lighter neutrino state and to a massless particle, namely photons, dark photons, axion-like particles and gravitons. We have shown that the neutrino evolution accounting for the decays will be governed by the Lindblad master equation, in which the decoherence parameters are proportional to the neutrino decay rate.

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42

GUO, WAN-LEI, YUE-LIANG WU e YU-FENG ZHOU. "DARK MATTER CANDIDATES IN LEFT-RIGHT SYMMETRIC MODELS". International Journal of Modern Physics D 20, n. 08 (15 agosto 2011): 1389–97. http://dx.doi.org/10.1142/s0218271811019578.

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Abstract (sommario):

We discuss an extended left-right symmetric model in which the decay of DM particle is induced by tiny soft charge-conjugation violating interactions, and calculate the spectra for cosmic-ray positrons, neutrinos and gamma-rays. The DM signals in the flux of high energy neutrinos can be significantly enhanced, as the triplets couple to both charged leptons and neutrinos. The predicted neutrino-induced muon flux can be several times larger than the case in which DM particle only directly decays into charged leptons. In addition, the charged components of the triplet give extra contributions to the high energy gamma-rays through internal bremsstrahlung process.

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43

HE, XIAO-GANG, SHU-YU HO, JUSAK TANDEAN e HO-CHIN TSAI. "SCALAR DARK MATTER AND STANDARD MODEL WITH FOUR GENERATIONS". International Journal of Modern Physics D 20, n. 08 (15 agosto 2011): 1423–31. http://dx.doi.org/10.1142/s0218271811019608.

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Abstract (sommario):

This talk is based on the previous paper [X. G. He et al., Phys. Rev. D82 (2010) 035016]. We consider a scalar dark-matter model, the SM4+D, consisting of the standard model with four generations (SM4) and a real gauge-singlet scalar called darkon, D, as the weakly interacting massive particle (WIMP) dark-matter (DM) candidate. We explore constraints on the darkon sector of the SM4+D from WIMP DM direct-search experiments, and from the decay of a B meson into a kaon plus missing energy. Since the darkon-Higgs interaction may give rise to considerable enhancement of the Higgs invisible decay mode, the existence of the darkon could lead to the weakening or evasion of some of the restrictions on the Higgs mass in the presence of fourth-generation quarks. In addition, it can affect the flavor-changing decays of these new heavy quarks into a lighter quark and the Higgs boson, as the Higgs may subsequently decay invisibly. Therefore, we also study these flavor-changing neutral transitions involving the darkon, as well as the corresponding top-quark decay t → cDD, some of which may be observable at the Tevatron or LHC and thus provide additional tests for the SM4+D.

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44

Salvio, Alberto, e Simone Scollo. "Axion–Sterile Neutrino Dark Matter". Universe 7, n. 10 (23 settembre 2021): 354. http://dx.doi.org/10.3390/universe7100354.

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Abstract (sommario):

Extending the standard model with three right-handed neutrinos and a simple QCD axion sector can account for neutrino oscillations, dark matter and baryon asymmetry; at the same time, it solves the strong CP problem, stabilizes the electroweak vacuum and can implement critical Higgs inflation (satisfying all current observational bounds). We perform here a general analysis of dark matter (DM) in such a model, which we call the aνMSM. Although critical Higgs inflation features a (quasi) inflection point of the inflaton potential, we show that DM cannot receive a contribution from primordial black holes in the aνMSM. This leads to a multicomponent axion–sterile neutrino DM and allows us to relate the axion parameters, such as the axion decay constant, to the neutrino parameters. We include several DM production mechanisms: the axion production via misalignment and decay of topological defects as well as the sterile neutrino production through the resonant and non-resonant mechanisms and in the recently proposed CPT-symmetric universe.

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45

Shtanov, Yu. "Cosmic neutrino from the decay of the scalaron dark matter". Bulletin of Taras Shevchenko National University of Kyiv. Astronomy, n. 66 (2022): 5–7. http://dx.doi.org/10.17721/btsnua.2022.66.5-7.

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Abstract (sommario):

The scalaron dark mater in F(R) gravity theory can decay into pairs of massive neutrino. We calculate the corresponding decay width and the current neutrino abundance and spectrum in the universe. The obtained neutrino flux turns out to be very small compared to the solar neutrino flux at Earth at similar energies.

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46

Gardner, Susan, e Mohammadreza Zakeri. "Probing Dark Sectors with Neutron Stars". Universe 10, n. 2 (1 febbraio 2024): 67. http://dx.doi.org/10.3390/universe10020067.

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Abstract (sommario):

Tensions in the measurements of neutron and kaon weak decays, such as of the neutron lifetime, may speak to the existence of new particles and dynamics not present in the Standard Model (SM). In scenarios with dark sectors, particles that couple feebly to those of the SM appear. We offer a focused overview of such possibilities and describe how the observations of neutron stars, which probe either their structure or dynamics, limit them. In realizing these constraints, we highlight how the assessment of particle processes within dense baryonic matter impacts the emerging picture—and we emphasize both the flavor structure of the constraints and their broader connections to cogenesis models of dark matter and baryogenesis.

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47

Popa, Lucia Aurelia. "Dark Matter Sterile Neutrino from Scalar Decays". Universe 7, n. 8 (21 agosto 2021): 309. http://dx.doi.org/10.3390/universe7080309.

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Abstract (sommario):

We place constraints on DM sterile neutrino scalar decay production (SDP) assuming that sterile neutrinos representa fraction from the total Cold Dark Matter energy density. For the cosmological analysis we complement the CMB anisotropy measurements with CMB lensing gravitational potential measurements, that are sensitive to the DM distribution to high redshifts and with the cosmic shear data that constrain the gravitational potential at lower redshifts than CMB. We also use the most recent low-redshift BAO measurements that are insensitive to the non-linear effects, providing robust geometrical tests. We show that our datasets have enough sensitivity to constrain the sterile neutrino mass mνs and the mass fraction fS inside the co-moving free-streaming horizon. We find that the best fit value mνs=7.88±0.73 keV (68% CL) is in the parameter space of interest for DM sterile neutrino decay interpretation of the 3.5 keV X-ray line and that fS=0.86±0.07 (68% CL) is in agreement with the upper limit constraint on fS from the X-ray non-detection and Ly-α forest measurements that rejects fS=1 at 3σ. However, we expect that the future BAO and weak lensing surveys, such as EUCLID, will provide much more robust constraints.

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48

Saadat, Hassan, e Malihe Rostampour. "Dark Matter Density from Heavy Neutrino Decays". International Journal of Theoretical Physics 51, n. 10 (25 aprile 2012): 3021–26. http://dx.doi.org/10.1007/s10773-012-1184-9.

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49

Barger, V., S. L. Glashow, D. Marfatia e K. Whisnant. "Neutrinoless double beta decay can constrain neutrino dark matter". Physics Letters B 532, n. 1-2 (aprile 2002): 15–18. http://dx.doi.org/10.1016/s0370-2693(02)01531-9.

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50

FARZAN, Y. "STRATEGIES TO LINK TINY NEUTRINO MASSES WITH HUGE MISSING MASS OF THE UNIVERSE". International Journal of Modern Physics A 26, n. 15 (20 giugno 2011): 2461–85. http://dx.doi.org/10.1142/s0217751x11053572.

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Abstract (sommario):

With the start of the LHC, interest in electroweak scale models for the neutrino mass has grown. In this paper, we review two specific models that simultaneously explain neutrino masses and provide a suitable DM candidate. We discuss the implications of these models for various observations and experiments including the LHC, Lepton Flavor Violating (LFV) rare decays, direct and indirect dark matter searches and kaon decay.

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