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Journal articles on the topic 'GeV excess'

Author: Grafiati

Published: 14 March 2023

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1

Cynolter, G., J. Kovács, and E. Lendvai. "Diphoton excess and VV-scattering." Modern Physics Letters A 31, no. 22 (July 14, 2016): 1650133. http://dx.doi.org/10.1142/s0217732316501339.

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We consider minimal effective interactions of the 750 GeV mass resonance observed recently by ATLAS and CMS. Assuming a new scalar and gauge invariant effective interactions leads to nontrivial two-particle scattering amplitudes with asymptotic gauge boson states. The longitudinally polarized W[Formula: see text] and Z bosons interacting via dimension-five effective operators provide stringent constraints on the validity of the effective model. The large width found by ATLAS implying a bound of approximately 500 GeV already below the resonance, turns this scenario unlikely. For production mainly in gluon fusion, we get an upper bound of [Formula: see text] 1.3 TeV and strong limits on the masses of the underlying vector-like fermions are given.

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2

Chernyshov, Dmitry O., Andrei E. Egorov, Vladimir A. Dogiel, and Alexei V. Ivlev. "On a Possible Origin of the Gamma-ray Excess around the Galactic Center." Symmetry 13, no. 8 (August 5, 2021): 1432. http://dx.doi.org/10.3390/sym13081432.

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Recent observations of gamma rays with the Fermi Large Area Telescope (LAT) in the direction of the inner galaxy revealed a mysterious excess of GeV. Its intensity is significantly above predictions of the standard model of cosmic rays (CRs) generation and propagation with a peak in the spectrum around a few GeV. Popular interpretations of this excess are that it is due to either spherically distributed annihilating dark matter (DM) or an abnormal population of millisecond pulsars. We suggest an alternative explanation of the excess through the CR interactions with molecular clouds in the Galactic Center (GC) region. We assumed that the excess could be imitated by the emission of molecular clouds with depleted density of CRs with energies below ∼10 GeV inside. A novelty of our work is in detailed elaboration of the depletion mechanism of CRs with the mentioned energies through the “barrier” near the cloud edge formed by the self-excited MHD turbulence. This depletion of CRs inside the clouds may be a reason for the deficit of gamma rays from the Central Molecular Zone (CMZ) at energies below a few GeV. This in turn changes the ratio between various emission components at those energies and may potentially absorb the GeV excess by a simple renormalization of key components.

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3

Heinemeyer, S. "The 750 GeV diphoton excess and SUSY." International Journal of Modern Physics A 31, no. 17 (June 20, 2016): 1630023. http://dx.doi.org/10.1142/s0217751x16300234.

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The LHC experiments ATLAS and CMS have reported an excess in the diphoton spectrum at [Formula: see text][Formula: see text]750 GeV. At the same time the motivation for Supersymmetry (SUSY) remains unbowed. Consequently, we review briefly the proposals to explain this excess in SUSY, focusing on “pure” (N)MSSM solutions. We then review in more detail a proposal to realize this excess within the NMSSM. In this particular scenario a Higgs boson with mass around 750 GeV decays to two light pseudo-scalar Higgs bosons. Via mixing with the pion these pseudo-scalars decay into a pair of highly collimated photons, which are identified as one photon, thus resulting in the observed signal.

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4

Yang, Shuai. "e+e− Pair Production at Very Low Transverse Mometum in Au+Au Collisions at s NN = 200 GeV and U+U Collisions at sNN = 193 GeV at STAR." International Journal of Modern Physics: Conference Series 46 (January 2018): 1860013. http://dx.doi.org/10.1142/s2010194518600133.

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We present the first measurements of [Formula: see text] pair production at very low transverse momentum ([Formula: see text] 0.15 GeV/[Formula: see text]) in Au + Au collisions at [Formula: see text] = 200 GeV and U + U collisions at [Formula: see text] = 193 GeV using the STAR detector at the Relativistic Heavy Ion Collider. A significant excess, with respect to known hadronic contributions, is observed in 60-80% central heavy-ion collisions over the whole [Formula: see text] range. Remarkably, the excess almost entirely happens below [Formula: see text] 0.15 GeV/[Formula: see text], and can not be explained by a theoretical model calculation incorporating in-medium broadened [Formula: see text] spectral function. Moreover, the observed excess yield has no significant centrality dependence. In addition, the steepness of [Formula: see text] distribution exhibits mild invariant mass and collision species dependence.

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5

Chan, Man. "Relieving Tensions Related to the Dark Matter Interpretation of the Fermi-LAT Data." Galaxies 6, no. 3 (August 29, 2018): 92. http://dx.doi.org/10.3390/galaxies6030092.

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Recently, many studies indicate that the GeV gamma ray excess signal from the central Milky Way can be best explained by ∼40–50 GeV dark matter annihilating via the b b ¯ channel. However, this model appears to be disfavored by the recent Fermi-LAT data for dwarf spheroidal galaxies and the constraint from synchrotron radiation. In this article, we describe a consistent picture to relieve the tensions between the dark matter annihilation model and the observations. We show that a baryonic feedback process is the key to alleviate the tensions and the ∼40–50 GeV dark matter model is still the best one to account for the GeV gamma ray excess in the Milky Way.

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6

Huang, Xiaoyuan, Torsten Enßlin, and Marco Selig. "GeV excess and phenomenological astrophysics modeling." Journal of Physics: Conference Series 718 (May 2016): 042029. http://dx.doi.org/10.1088/1742-6596/718/4/042029.

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7

Salfeld-Nebgen, Jakob. "Search for the Higgs Boson decaying into tau pairs." International Journal of Modern Physics: Conference Series 31 (January 2014): 1460303. http://dx.doi.org/10.1142/s2010194514603032.

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A search for the Standard Model Higgs Boson decaying into τ pairs is performed using events recorded by the CMS experiment at the LHC in 2011 and 2012. An excess of events is observed over a broad range of Higgs mass hypotheses, with a maximum local significance of 2.93 standard deviations at mH = 120 GeV. The excess is compatible with the presence of a standard-model Higgs boson of mass 125 GeV/c2.

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8

Yang, Chi. "Coherent e+e- production at very low transverse momentum at STAR." EPJ Web of Conferences 171 (2018): 18016. http://dx.doi.org/10.1051/epjconf/201817118016.

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We report the measurements of e+e- pair production at very low e+e- pair transverse momentum (pT < 0.15 GeV/c) in Au+Au collisions at [see formula in PDF] = 200 GeV and U+U collisions at [see formula in PDF] = 193 GeV using the STAR detector at the Relativistic Heavy Ion Collider. In 60-80% centrality, significant excesses are observed with respect to hadronic cocktails in both Au+Au and U+U collisions. These excess yields can not be explained by a theoretical model calculation incorporating in-medium broadened ρ spectral function. Additionally, the [see formula in PDF] distribution for excess yield is shown and found to be exponential at very low pT.

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9

Bartels, Richard, and Christoph Weniger. "Millisecond Pulsars in the Galactic Bulge? An Extended Discussion on the Wavelet Analysis of the Fermi-LAT data." Proceedings of the International Astronomical Union 11, S322 (July 2016): 193–96. http://dx.doi.org/10.1017/s174392131601200x.

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AbstractA clear excess in the Fermi-LAT data is present at energies around a few GeV. The spectrum of this so-called ’GeV excess’ is remarkably similar to the expected annihilation signal of WIMP dark matter. However, a large bulge population of millisecond pulsars living below the Fermi–LAT detection threshold could also explain the excess spectrum. In a recent work we optimized the search for sub-threshold sources, by applying a wavelet transform to the Fermi–LAT gamma-ray data. In the Inner-Galaxy the wavelet signal is significantly enhanced, providing supportive evidence for the point source interpretation of the excess. In these proceedings we will extent our previous work with a spectral analysis and elaborate on the potential contamination from substructures in the gas.

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10

Biekötter, T., M. Chakraborti, and S. Heinemeyer. "The “96 GeV excess” at the LHC." International Journal of Modern Physics A 36, no. 22 (July 30, 2021): 2142018. http://dx.doi.org/10.1142/s0217751x21420185.

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The CMS collaboration reported an intriguing [Formula: see text] (local) excess at 96 GeV in the light Higgs-boson search in the diphoton decay mode. This mass coincides with a [Formula: see text] (local) excess in the [Formula: see text] final state at LEP. We briefly review the proposed combined interpretations for the two excesses. In more detail, we review the interpretation of this possible signal as the lightest Higgs boson in the 2 Higgs Doublet Model with an additional real Higgs singlet (N2HDM). We show which channels have the best prospects for the discovery of additional Higgs bosons at the upcoming Run 3 of the LHC.

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11

Das, Arindam, Nobuchika Okada, and Osamu Seto. "Galactic Center Excess by Higgs Portal Dark Matter." International Journal of Modern Physics: Conference Series 43 (January 2016): 1660198. http://dx.doi.org/10.1142/s2010194516601988.

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A [Formula: see text] parity odd real scalar is a good candidate for dark matter in the present Universe. We consider models contain two Higgs doublet fields and one real scalar dark matter particle with mass in the range of [Formula: see text] GeV and annihilating into a [Formula: see text] pair, or with about [Formula: see text] GeV mass and annihilating into tau lepton pair. Those annihilation modes suitably explain the observed excess of the gamma-ray flux from the Galactic Center. We identify the parameter region of the model that can fit the gamma-ray excess and satisfy phenomenological constraints, such as the observed dark matter relic density and the null results of direct dark matter search experiments. Most of the parameter region is found to be within the search reach of various future experiments.

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12

Ding, Ran, Li Huang, Tianjun Li, and Bin Zhu. "Interpreting 750 GeV diphoton excess with R-parity violating supersymmetry." International Journal of Modern Physics A 32, no. 02n03 (January 25, 2017): 1750014. http://dx.doi.org/10.1142/s0217751x17500142.

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We propose a supersymmetric explanation of the diphoton excess in the Minimal Supersymmetric Standard Model (MSSM) with the leptonic R-parity violation. In our model, sneutrino serves as the 750 GeV resonance and produced through quark–antiquark annihilation. With introducing appropriate trilinear soft parameters, we show that the diphoton branching ratio is significantly enhanced compared with the conventional MSSM. For current dijet and W-pair LHC constraints, we can successfully fit the observed diphoton signal rate in sizeable parameter regions, the resulting parameter space strongly favor the masses of light smuon and stau within the range from 375–500 GeV, which depends on the choice of electroweakino masses and soft trilinear terms. While after taking into account the compatibility of diphoton excess between the 8 TeV and 13 TeV LHC, only the coupling involved with the second generation quarks is survived. In this case, the corresponding parameter space favors a narrow mass range of smuon and stau with [Formula: see text]. Even if the 750 GeV diphoton excesses were not confirmed by the ATLAS and CMS experiments, we point out that our proposal can still be used to explain the current and future tentative diphoton excesses.

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13

Büsching, I., M. Pohl, and R. Schlickeiser. "Excess GeV radiation and cosmic ray origin." Astronomy & Astrophysics 377, no. 3 (October 2001): 1056–62. http://dx.doi.org/10.1051/0004-6361:20011125.

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14

Borah, Debasish, Sudhanwa Patra, and Shibananda Sahoo. "Subdominant left–right scalar dark matter as origin of the 750 GeV di-photon excess at LHC." International Journal of Modern Physics A 31, no. 17 (June 20, 2016): 1650097. http://dx.doi.org/10.1142/s0217751x16500974.

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We study the possibility of explaining the recently reported 750 GeV di-photon excess at LHC within the framework of a left–right symmetric model. The 750 GeV neutral scalar in the model is dominantly an admixture of neutral components of scalar bidoublets with a tiny fraction of neutral scalar triplet. Incorporating [Formula: see text] septuplet scalar pairs into the model, we enhance the partial decay width of the 750 GeV neutral scalar into di-photons through charged septuplet components in loop while keeping the neutral septuplet components as subdominant dark matter candidates. The model also predicts the decay width of the 750 GeV scalar to be around 36 GeV to be either confirmed or ruled out by future LHC data. The requirement of producing the correct di-photon signal automatically keeps the septuplet dark matter abundance subdominant in agreement with bounds from direct and indirect detection experiments. We then briefly discuss different possibilities to account for the remaining dark matter component of the Universe in terms of other particle candidates whose stability arises either due to remnant discrete symmetry after spontaneous breaking of [Formula: see text] or due to high [Formula: see text]-dimension forbidding their decay into lighter particles.

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15

Matsuzaki, Shinya, and Koichi Yamawaki. "750 GeV diphoton signal from one-family walking technipion." Modern Physics Letters A 31, no. 17 (June 7, 2016): 1630016. http://dx.doi.org/10.1142/s0217732316300160.

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The ATLAS and CMS groups have recently reported an excess at around 750 GeV with the local significance by about 3[Formula: see text] in the diphoton channel at the 13 TeV LHC. We give a possible explanation for the excess by a composite pseudo scalar [Formula: see text] predicted in the one-family model of walking technicolor.

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16

Gómez-Ceballos, G. "SEARCH FOR CHARGED HIGGS BOSONS IN E+E- COLLISIONS AT LEP AT THE DELPHI EXPERIMENT." International Journal of Modern Physics A 16, supp01b (September 2001): 839–42. http://dx.doi.org/10.1142/s0217751x01008254.

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A search for pair produced charged Higgs bosons was performed in the high energy data collected by the DELPHI detector at LEP II at centre-of-mass energies from 183 GeV to 208 GeV. The three different final states, τντν, [Formula: see text] and [Formula: see text] were considered. No excess of data compared to the expected Standard Model processes was observed and the existence of a charged Higgs boson with mass lower than 75.0 GeV / c 2 is excluded at 95% confidence level.

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17

Zha, Wangmei. "Excess of J/ψ Production at Very Low Transverse Momenta in A+A Collisions from STAR." International Journal of Modern Physics: Conference Series 46 (January 2018): 1860012. http://dx.doi.org/10.1142/s2010194518600121.

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A significant excess of [Formula: see text] yield at very low transverse momentum ([Formula: see text] GeV/c) has been observed by the ALICE Collaboration in peripheral Pb+Pb collisions, which points to evidence of coherent photoproduction of [Formula: see text] in violent hadronic interactions. The survival of photoproduced [Formula: see text] merits more experimental investigations. In this article, we report on the STAR measurements of [Formula: see text] production at very low transverse momenta ([Formula: see text]) in hadronic Au+Au collisions at [Formula: see text] = 200 GeV and U+U collisions at [Formula: see text] = 193 GeV at mid-rapidity. Centrality dependence of [Formula: see text] yields and nuclear modification factors at very low [Formula: see text] are presented.

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18

Zhou, Jian. "Low-p_T μ⁺μ⁻ pair production in Au+Au collisions at √S_NN = 200 GeV at STAR." EPJ Web of Conferences 259 (2022): 13014. http://dx.doi.org/10.1051/epjconf/202225913014.

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We report the measurements of μ+μ− pair production for pT < 0.10 GeV/c in 40-80% Au+Au collisions at √SNN = 200 GeV at STAR. A significant enhancement with respect to the hadronic cocktail is observed. The pT2 and ∆ϕ distributions of the excess yields are also reported and compared with model calculations. The EPA-QED calculations can describe the data very well within uncertainties.

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19

Calore, Francesca, Ilias Cholis, and Christoph Weniger. "Background model systematics for the Fermi GeV excess." Journal of Cosmology and Astroparticle Physics 2015, no. 03 (March 23, 2015): 038. http://dx.doi.org/10.1088/1475-7516/2015/03/038.

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20

Fabbrichesi, Marco. "The LHC di-photon excess at 750 GeV." EPJ Web of Conferences 129 (2016): 00001. http://dx.doi.org/10.1051/epjconf/201612900001.

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21

Harigaya, Keisuke, and Yasunori Nomura. "Composite models for the 750 GeV diphoton excess." Physics Letters B 754 (March 2016): 151–56. http://dx.doi.org/10.1016/j.physletb.2016.01.026.

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22

Salvio, Alberto, and Anupam Mazumdar. "Higgs stability and the 750 GeV diphoton excess." Physics Letters B 755 (April 2016): 469–74. http://dx.doi.org/10.1016/j.physletb.2016.02.057.

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23

Badziak, Marcin, Marek Olechowski, Stefan Pokorski, and Kazuki Sakurai. "Interpreting 750 GeV diphoton excess in plain NMSSM." Physics Letters B 760 (September 2016): 228–35. http://dx.doi.org/10.1016/j.physletb.2016.06.057.

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24

Sun, Xiao-Na, Rui-Zhi Yang, Bing Liu, Shao-Qiang Xi, and Xiang-Yu Wang. "Tentative evidence of spatially extended GeV emission from SS433/W50." Astronomy & Astrophysics 626 (June 2019): A113. http://dx.doi.org/10.1051/0004-6361/201935621.

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We have analyzed ten years of the Fermi Large Area Telescope data toward the SS433/W50 region. With the latest source catalog and diffuse background models, the γ-ray excess from SS433/W50 is detected with a significance of ~6σ in the photon energy range of 500 MeV–10 GeV. Our analysis indicates that an extended flat disk morphology is preferred over a point-source description, suggesting that the GeV emission region is much larger than that of the TeV emission detected by the High Altitude Water Cherenkov (HAWC) telescope. The size of the GeV emission is instead consistent with the extent of the radio nebula W50, a supernova remnant being distorted by the jets, so we suggest that the GeV emission may originate from this supernova remnant. The spectral result of the GeV emission is also consistent with a supernova remnant origin. Furthermore, we derive the GeV flux upper limits on the TeV emission region, which put moderate constraints on the leptonic models to explain the multiwavelength data.

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25

Çiçi, Ali, Shaaban Khalil, Büşra Niş, and Cem Salih Ün. "The 28 GeV dimuon excess in lepton specific THDM." Nuclear Physics B 977 (April 2022): 115728. http://dx.doi.org/10.1016/j.nuclphysb.2022.115728.

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26

Ko, P., and Yong Tang. "Dark Higgs channel for Fermi GeV γ-ray excess." Journal of Cosmology and Astroparticle Physics 2016, no. 02 (February 4, 2016): 011. http://dx.doi.org/10.1088/1475-7516/2016/02/011.

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27

Nevzorov, Roman, and Anthony Thomas. "E6inspired composite Higgs model and 750 GeV diphoton excess." EPJ Web of Conferences 125 (2016): 02021. http://dx.doi.org/10.1051/epjconf/201612502021.

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28

Bhakta, D., J. S. Deneva, D. A. Frail, F. de Gasperin, H. T. Intema, P. Jagannathan, and K. P. Mooley. "Searching for pulsars associated with the Fermi GeV excess." Monthly Notices of the Royal Astronomical Society 468, no. 3 (March 16, 2017): 2526–31. http://dx.doi.org/10.1093/mnras/stx656.

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29

Zhang, Jue, and Shun Zhou. "Electroweak vacuum stability and diphoton excess at 750 GeV." Chinese Physics C 40, no. 8 (July 29, 2016): 081001. http://dx.doi.org/10.1088/1674-1137/40/8/081001.

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30

Ackermann, M., M. Ajello, A. Albert, W. B. Atwood, L. Baldini, J. Ballet, G. Barbiellini, et al. "TheFermiGalactic Center GeV Excess and Implications for Dark Matter." Astrophysical Journal 840, no. 1 (May 4, 2017): 43. http://dx.doi.org/10.3847/1538-4357/aa6cab.

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31

Modak, Tanmoy, Soumya Sadhukhan, and Rahul Srivastava. "750 GeV diphoton excess from gauged B − L symmetry." Physics Letters B 756 (May 2016): 405–12. http://dx.doi.org/10.1016/j.physletb.2016.03.021.

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32

Baek, Seungwon, and Jae-hyeon Park. "LHC 750 GeV diphoton excess and muon ( g − 2)." Physics Letters B 758 (July 2016): 416–22. http://dx.doi.org/10.1016/j.physletb.2016.05.040.

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33

ARBUZOV, BORIS A., and IVAN V. ZAITSEV. "CDF Wjj ANOMALY AS A NONPERTURBATIVE EFFECT OF THE ELECTROWEAK INTERACTION." International Journal of Modern Physics A 27, no. 03n04 (February 10, 2012): 1250012. http://dx.doi.org/10.1142/s0217751x12500121.

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The recently reported CDF excess at 120–160 GeV in invariant mass distribution of jet pairs accompanying W-boson1 is tentatively interpreted as a bound state of two W decaying to quark–antiquark pair. Nonperturbative effects of EW interaction obtained by application of Bogoliubov compensation approach lead to such bound state due to existence of anomalous three-boson gauge-invariant effective interaction. The application of this scheme gives satisfactory agreement with existing data without any adjusting parameter but the bound state mass 145 GeV.

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34

Wang, Ruiguang, Zhongqiang Yu, Yuqian Ma, Linkai Ding, Qingqi Zhu, Zhiguo Yao, Xinhua Ma, Yupeng Xu, and Changgen Yang. "GeV Proton Detection in the 8 November 2000 Solar Event." Universe 8, no. 5 (May 20, 2022): 287. http://dx.doi.org/10.3390/universe8050287.

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In this study, we analyze the L3 precision muon spectrometer data from November 2000. The results showed that a 4.7σ muon excess appeared at a time coincident with the solar flare of 8 November 2000. This muon excess corresponded to primary protons above 40 GeV, coming from a sky cell of solid angle 0.048 sr. The probability of being a background fluctuation was estimated to be about 0.1%. It is interesting and noteworthy that an M-class solar flare may also accelerate solar protons to such high energies.

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35

De La Torre Luque, Pedro. "Combined analyses of the antiproton production from cosmic-ray interactions and its possible dark matter origin." Journal of Cosmology and Astroparticle Physics 2021, no. 11 (November 1, 2021): 018. http://dx.doi.org/10.1088/1475-7516/2021/11/018.

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Abstract Recent cosmic-ray (CR) studies have claimed the possibility of an excess on the antiproton flux over the predicted models at around 10 GeV, which can be the signature of dark matter annihilating into hadronic final states that subsequently form antiprotons. However, this excess is subject to many uncertainties related to the evaluation of the antiproton spectrum produced from spallation interactions of CRs. In this work, we implement a combined Markov-Chain Monte Carlo analysis of the secondary ratios of B, Be and Li and the antiproton-to-proton ratio (p̅/p), while also including nuisance parameters to consider the uncertainties related to the spallation cross sections. This study allows us to constrain the Galactic halo height and the rest of propagation parameters, evaluate the impact of cross sections uncertainties in the determination of the antiproton spectrum and test the origin of the excess of antiprotons. In this way, we provide a set of propagation parameters and scale factors for renormalizing the cross sections parametrizations that allow us to reproduce all the ratios of B, Be, Li and p̅ simultaneously. We show that the energy dependence of the p̅/p ratio is compatible with a pure secondary origin. In particular, we find that the energy dependence of the evaluated p̅/p spectrum matches that observed from AMS-02 data at energies above ∼3 GeV, although there is still a constant ∼10% excess of p̅ over our prediction. We discuss that this discrepancy is more likely explained from a ∼10% scaling in the cross sections of antiproton production, rather than a component of dark matter leading to antiprotons. In particular, we find that the best-fit WIMP mass (∼300 GeV) needed to explain the discrepancy lies above the constraints from most indirect searches of dark matter and the resultant fit is poorer than with a cross sections scaling.

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36

TRIGGER, ISABEL. "SEARCH FOR SCALAR PARTNERS OF FERMIONS BY THE OPAL COLLABORATION AT LEP." International Journal of Modern Physics A 16, supp01b (September 2001): 807–9. http://dx.doi.org/10.1142/s0217751x01008151.

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Search for scalar partners of fermions, predicted by supersymmetric theories, are performed using a data sample of about 520 pb -1 taken at center-of-mass energies in the range 183–209 GeV. As excess of candidates is found, cross-section limits are calculated.

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37

Junk, Thomas R., and Aurelio Juste. "Review of physics results from the Tevatron: Higgs boson physics." International Journal of Modern Physics A 30, no. 06 (February 27, 2015): 1541006. http://dx.doi.org/10.1142/s0217751x15410067.

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We review the techniques and results of the searches for the Higgs boson performed by the two Tevatron collaborations, CDF and DØ. The Higgs boson predicted by the Standard Model was sought in the mass range 90 GeV < mH < 200 GeV in all main production modes at the Tevatron: gluon–gluon fusion, WH and ZH associated production, vector boson fusion, and [Formula: see text] production, and in five main decay modes: [Formula: see text], H→τ+τ-, H→WW(*), H→ZZ(*) and H→γγ. An excess of events was seen in the [Formula: see text] searches consistent with a Standard Model Higgs boson with a mass in the range 115 GeV < mH < 135 GeV . Assuming a Higgs boson mass of mH = 125 GeV , studies of Higgs boson properties were performed, including measurements of the product of the cross section times the branching ratio in various production and decay modes, constraints on Higgs boson couplings to fermions and vector bosons, and tests of spin and parity. We also summarize the results of searches for supersymmetric Higgs bosons, and Higgs bosons in other extensions of the Standard Model.

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38

YAO, WEIMING. "STANDARD MODEL HIGGS SEARCHES AT THE TEVATRON." International Journal of Modern Physics A 27, no. 24 (September 28, 2012): 1230023. http://dx.doi.org/10.1142/s0217751x12300232.

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We present the results of direct searches for the Standard Model Higgs boson at the Tevatron. Results are derived from the complete Tevatron Run II dataset, with a measured integrated luminosity of 10 fb-1 of proton–antiproton data. The searches are performed for assumed Higgs masses between 90 and 200 GeV /c2. We observe an excess of events in the data compared with the background predictions, which is most significant in the mass range between 115 and 135 GeV /c2, consistent with the Higgs-like particle recently observed by ATLAS and CMS. The largest local significance is 2.7 standard deviations, corresponding to a global significance of 2.2 standard deviations. We also combine separate searches for [Formula: see text] and H→W+W-, and find that the excess is concentrated in the [Formula: see text] channel, although the results in the H→W+W- channel are still consistent with the possible presence of a low-mass Higgs boson.

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39

FAN, YI-ZHONG, BING ZHANG, and JIN CHANG. "ELECTRON/POSITRON EXCESSES IN THE COSMIC RAY SPECTRUM AND POSSIBLE INTERPRETATIONS." International Journal of Modern Physics D 19, no. 13 (November 2010): 2011–58. http://dx.doi.org/10.1142/s0218271810018268.

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The data collected by ATIC, PPB-BETS, FERMI-LAT and HESS all indicate that there is an electron/positron excess in the cosmic ray energy spectrum above ~100 GeV, although different instrumental teams do not agree on the detailed spectral shape. PAMELA also reported clearly the excessive feature of the fraction of positron above several GeV, but with no excess in antiprotons. Here we review the observational status and theoretical models of this interesting observational feature. We pay special attention to various physical interpretations proposed in the literature, including modified supernova remnant models for the e± background, new astrophysical sources, and new physics (the dark matter models). We suggest that although most models can make a case to interpret the data, with the current observational constraints the dark matter interpretations, especially those invoking annihilation, require much more exotic assumptions than some other astrophysical interpretations. Future observations may present some "smoking-gun" observational tests to differentiate different models and to identify the correct interpretation of the phenomenon.

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Yokkaichi, S., H. En'yo, M. Naruki, R. Muto, T. Tabaru, J. Chiba, M. Ieiri, et al. "STUDY OF IN-MEDIUM MESON MODIFICATION IN 12 GeV p + A REACTIONS." International Journal of Modern Physics A 22, no. 02n03 (January 30, 2007): 397–405. http://dx.doi.org/10.1142/s0217751x07035586.

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Invariant mass spectra of low-mass vector mesons in the e+e- channel are measured in 12 GeV p + C and p + Cu reactions [Formula: see text] at the KEK Proton Synchrotron. Significant excess is observed at the low-mass side of ω meson peak over the known hadronic sources both in the C and Cu target data. Also below the ϕ meson peak, an excess is found in the Cu target data for slowly moving mesons whose βγ is less than 1.25. They can be interpreted as signatures of the spectral modification of vector mesons in cold nuclear matter.

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Calore, Francesca, Nassim Bozorgnia, Mark Lovell, Gianfranco Bertone, Matthieu Schaller, Carlos S. Frenk, Robert A. Crain, Joop Schaye, Tom Theuns, and James W. Trayford. "The Fermi GeV excess: challenges for the dark matter interpretation." Journal of Physics: Conference Series 718 (May 2016): 042010. http://dx.doi.org/10.1088/1742-6596/718/4/042010.

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Kanemura, Shinya, Kenji Nishiwaki, Hiroshi Okada, Yuta Orikasa, Seong Chan Park, and Ryoutaro Watanabe. "LHC 750 GeV diphoton excess in a radiative seesaw model." Progress of Theoretical and Experimental Physics 2016, no. 12 (December 2016): 123B04. http://dx.doi.org/10.1093/ptep/ptw164.

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Kong, Kyoungchul, and Jong-Chul Park. "Bounds on dark matter interpretation of Fermi-LAT GeV excess." Nuclear Physics B 888 (November 2014): 154–68. http://dx.doi.org/10.1016/j.nuclphysb.2014.09.014.

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Cao, Junjie, Liangliang Shang, Wei Su, Fei Wang, and Yang Zhang. "Interpreting the 750 GeV diphoton excess within topflavor seesaw model." Nuclear Physics B 911 (October 2016): 447–70. http://dx.doi.org/10.1016/j.nuclphysb.2016.08.018.

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Dalchenko, Mykhailo, Bhaskar Dutta, Yu Gao, Tathagata Ghosh, and Teruki Kamon. "Exploring the jet multiplicity in the 750 GeV diphoton excess." Physics Letters B 761 (October 2016): 77–80. http://dx.doi.org/10.1016/j.physletb.2016.08.012.

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von Buddenbrook, Stefan, Alan S. Cornell, Deepak Kar, Mukesh Kumar, Bruce Mellado, and Robert G. Reed. "A heavy scalar of mass 270 GeV and its possible connection to the 750 GeV excess." Journal of Physics: Conference Series 802 (January 2017): 012001. http://dx.doi.org/10.1088/1742-6596/802/1/012001.

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Liu, Ning, Wenyu Wang, Mengchao Zhang, and Rui Zheng. "750 GeV diphoton resonance in a vector-like extension of Hill model at a 100 TeV hadron collider." International Journal of Modern Physics A 31, no. 25 (September 8, 2016): 1650145. http://dx.doi.org/10.1142/s0217751x16501451.

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In this paper, we study the recent 750 GeV diphoton excess in the Hill model with vector-like fermions. The singlet-like Hill boson is chosen as the 750 GeV diphoton resonance. Such a scalar is mainly produced by gluon fusion via vector-like top and bottom quark loops and decays to diphoton via the vector-like quark and lepton loops. Under the current experimental and theoretical constraints, we find that the mixing angle of the singlet and doublet Higgs bosons lies within [Formula: see text] and the 750 GeV diphoton cross-section can be maximally enhanced to about 6 fb at 13 TeV LHC. Moreover, we find that the Hill boson pair production in [Formula: see text] channel can be probed at [Formula: see text] significance if [Formula: see text] and [Formula: see text] at a 100 TeV collider with 3000 fb[Formula: see text] luminosity.

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PRODANOVIC, T., B. FIELDS, and J. BEACOM. "Diffuse gamma rays from the Galactic Plane: Probing the “GeV excess” and identifying the “TeV excess”." Astroparticle Physics 27, no. 1 (February 2007): 10–20. http://dx.doi.org/10.1016/j.astropartphys.2006.08.007.

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Shao, Chengyu, Xiaopeng Cheng, Tam, Pak-Hin Thomas, Lili Yang, Yudong Cui, Partha Sarathi Pal, Zhongli Zhang, et al. "Is Fermi 1544-0649 a Misaligned Blazar? Discovering the Jet Structure with Very Long Baseline Interferometry." Astrophysical Journal 934, no. 1 (July 1, 2022): 39. http://dx.doi.org/10.3847/1538-4357/ac778c.

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Abstract Fermi J1544-0649 is a transient GeV source first detected during its GeV flares in 2017. Multiwavelength observations during the flaring time demonstrate variability and spectral energy distributions that are typical of a blazar. Other than the flare time, Fermi J1544-0649 is quiet in the GeV band and has looked rather like a quiet galaxy (2MASX J15441967-0649156) for a decade. Together with the broad absorption-lines-like feature we further explore the “misaligned blazar scenario.” We analyzed the Very Long Baseline Array (VLBA) and East Asian VLBI Network (EAVN) data from 2018 to 2020 and discovered the four jet components from Fermi J1544-0649. We found a viewing angle around 3.°7 to 7.°4. The lower limit of the viewing angle indicates a blazar with an extreme low duty cycle of gamma-ray emission; the upper limit of it supports the “misaligned blazar scenario.” Follow-up multiwavelength observations after 2018 show Fermi J1544-0649 remains quiet in GeV, X-ray, and optical bands. A multimessenger search of neutrinos is also performed, and an excess of 3.1σ significance is found for this source.

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FELIGIONI, LORENZO. "Searches for Technicolor Particles at DØ." International Journal of Modern Physics A 20, no. 15 (June 20, 2005): 3302–4. http://dx.doi.org/10.1142/s0217751x0502639x.

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We present preliminary results of searches for technirho (ρT) and techniomega (ωT) particles, using the decay channels (ρT), ωT → e+e- and [Formula: see text], where [Formula: see text], [Formula: see text]. These searches are based respectively on 200 pb-1 and 238 pb-1 of data collected in Run II of the Fermilab Tevatron. We select events with b–quark jets by identifying secondary vertices in the jets. We interpret our findings in terms of limits on the production of particles predicted by extended technicolor models. For the WπT analysis, in the absence of an excess over standard model background, we compute a 95% C.L. upper limit on the techniparticle production cross section for the mass combination m(ρT) = 200 GeV and m(πT) = 105 GeV of 6.4 pb. In the e+e- channel, for certain model parameters, we exclude the existence of degenerate ρT and ωT states with masses below 367 GeV; the most restrictive constraints on dilepton technicolor decays to date.

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