Tue·Jun 11, 2019Tuesday·June 11, 2019

1. 01*

   xBIT: an easy to use scanning tool with machine learning abilities

   Florian Staub🇩🇪

   xBIT is a tool for performing parameter scans in beyond the Standard Model theories. It's written in Python and fully open source. The main purpose of xBIT is to provide an easy to use tool to help phenomenologists with their daily task: exploring the parameter space of new models. It was developed under the impression of the SARAH/SPheno framework, but should be use-able with other tools as well that use the SLHA format to transfer data. It also supports by default MicrOmegas for dark matter calculations, HiggsBounds and HiggsSignals for checking the Higgs properties, and Vevacious for testing the vacuum stability. Classes for other tools can be added if necessary. In order to improve the efficiency of the parameter scans, the recently proposed 'Machine Learning Scan' approach is included. For this purpose, xBIT uses pyTorch to deal with artificial neural networks.

   hep-phhep-ex20 citations
2. 02*

   Physical projectors for multi-leg helicity amplitudes

   Tiziano Peraro🇨🇭 · Lorenzo Tancredi🇨🇭

   We present a method for building physical projector operators for multi-leg helicity amplitudes. For any helicity configuration of the external particles, we define a physical projector which singles out the corresponding helicity amplitude. For processes with more than four external legs, these physical projectors depend on significantly fewer tensor structures and exhibit a remarkable simplicity compared with projector operators defined with traditional approaches. As an example, we present analytic formulas for a complete set of projectors for five-gluon scattering. These have been validated by reproducing known results for five-gluon amplitudes up to one-loop.

   hep-phhep-thJHEP(2019)·93 citations
3. 03*

   Light Higgs bosons in the general NMSSM

   Kiwoon Choi🇰🇷 · Sang Hui Im🇰🇷 · Kwang Sik Jeong🇰🇷 · Chan Beom Park🇰🇷

   Physics beyond the Standard Model (SM) may manifest itself as small deviations from the SM predictions for Higgs signal strengths at 125 GeV. Then, a plausible and interesting possibility is that the Higgs sector is extended and at the weak scale there appears an additional Higgs boson weakly coupled to the SM sector. Combined with the LEP excess in $e^{+}{e}^{-}\to Z(h\to b\bar{b})$, the diphoton excess around 96 GeV recently reported by CMS may suggest such a possibility. We examine if those LEP and CMS excesses can be explained simultaneously by a singlet-like Higgs boson in the general next-to-minimal supersymmetric Standard Model (NMSSM). Higgs mixing in the NMSSM relies on the singlet coupling to the MSSM Higgs doublets and the higgsino mass parameter, and thus is subject to the constraints on these supersymmetric parameters. We find that the NMSSM can account for both the LEP and CMS excesses at 96 GeV while accommodating the observed 125 GeV SM-like Higgs boson. Interestingly, the required mixing angles constrain the heavy doublet Higgs boson to be heavier than about 500 GeV. We also show that the viable region of mixing parameter space is considerably modified if the higgsino mass parameter is around the weak scale, mainly because of the Higgs coupling to photons induced by the charged higgsinos.

   hep-phEPJC(2019)·58 citations
4. 04*

   Conformal invariance and singlet fermionic dark matter

   Yeong Gyun Kim🇰🇷 · Kang Young Lee🇰🇷 · Soo-hyeon Nam🇰🇷

   We study a classically scale-invariant model with an electroweak singlet complex scalar mediator together with an anomaly free set of two fermionic dark matters. We introduce $U(1{)}_X$ gauge symmetry with a new charge $X$ in the dark sector in order to stabilize the mass of the scalar singlet with a new gauge boson. Our conformally invariant scalar potential generates the electroweak symmetry breaking via the Coleman-Weinberg mechanism, and the new scalar singlet acquires its mass through radiative corrections of the fermionic dark matters and the new gauge boson as well as of the SM particles. Taking into account the collider bounds, we present the allowed region of new physics parameters satisfying the recent measurement of relic abundance. With the obtained parameter sets, we predict the elastic scattering cross section of the new singlet fermions into target nuclei for a direct detection of the dark matter. We also discuss the collider signatures and future discovery potentials of the new scalar and gauge boson.

   hep-phPRD(2019)·14 citations
5. 05*

   Overlap of electron shells in $\beta$ and double-$\beta$ decays

   M.I. Krivoruchenko🇷🇺 · K.S. Tyrin🇷🇺

   The $\beta$ and double-$\beta$ decay channels, which are not accompanied by excitation of the electron shells, are suppressed due to the nonorthogonality of the electron wave functions of the parent and daughter atoms. The effect is sensitive to the contribution of the outer electron shells. Since valence electrons participate in chemical bonding and collectivize in metals, the decay rates of the unstable nuclides are modified when they are embedded in a host material. Core electrons are less affected by the environment, and their overlap amplitudes are more stable. The suppression effect is estimated for ${\beta }^{-}$ decay of ${}^{87}$Kr, electron capture in ${}^{163}$Ho, and $2{\beta }^{-}$ decays of ${}^{76}$Ge, ${}^{100}$Mo, ${}^{130}$Te, and ${}^{136}$Xe. The overlap amplitude of the electron shells enters the relationship between the half-life of neutrinoless $2\beta$ decay and the effective electron neutrino Majorana mass.

   hep-phnucl-thEPJA(2020)·6 citations
6. 06*

   Parity odd Fragmentation Functions

   Weihua Yang🇨🇳

   Quantum chromodynamics is a non-Abelian gauge theory of strong interactions, in which the parity symmetry can be violated by the non-trivial $\theta$-vacuum tunneling effects. The $\theta$-vacuum induces the local parity odd domains. Those reactions that occur in these domains can be affected by the tunneling effects and quantities become parity odd. In this paper we consider the fragmentation process where parity odd fragmentation functions are introduced. We present the fragmentation functions by decomposing the quark-quark correlator. Among the total 16 fragmentation functions, 8 of them are parity conserved, and the others are parity violated. They have a one-to-one correspondence. Positivity bounds of these one dimensional fragmentation functions are shown. To be explicit, we also introduce a operator definition of the parity odd correlator. According to the definition, we give a proof that the parity odd fragmentation functions are local quantities and vanish when sum over all the hadrons h.

   hep-phInt.J.Mod.Phys.A(2019)·7 citations
7. 07*

   Fermion Dark Matter with $N_2$ Leptogenesis in Minimal Scotogenic Model

   Devabrat Mahanta🇮🇳 · Debasish Borah🇮🇳

   We study the possibility of singlet fermion dark matter (DM) and successful leptogenesis in minimal scotogenic model which also provides a common origin of DM and light neutrino masses. In this scenario, where the standard model (SM) is extended by three gauge singlet fermions and one additional scalar doublet, all odd under an in-built $Z_2$ symmetry, the lightest singlet fermion which also happens to be the lightest $Z_2$ odd particle, can be either thermal or non-thermal DM candidate depending upon the strength of its couplings with SM leptons and the $Z_2$ odd scalar doublet. In both the scenarios, the $Z_2$ odd scalar doublet plays a non-trivial role either by assisting coannihilation with thermal DM or by providing a source for non-thermal DM via decay. The heavier $Z_2$ odd singlet fermion produces a net lepton asymmetry through its out-of-equilibrium decay into SM leptons and $Z_2$ odd scalar doublet. We show that the requirement of producing the observed baryon asymmetry pushes the scale of leptogenesis in case of normal ordering of light neutrino masses to several order of magnitudes above TeV scale. In case of inverted ordering however, it is possible to have successful $N_2$ leptogenesis at a scale of few tens of TeV. Inclusion of lepton flavour effects lowers this scale of leptogenesis by around an order of magnitude in both the cases. Correct DM abundance can be realised either by thermal freeze-out or by freeze-in mechanism in different parts of the parameter space that can have interesting prospects for ongoing experiments.

   hep-phastro-ph.COJCAP(2019)·50 citations
8. 08*

   m_c and m_b from M_B_c and improved estimate of f_B_c and f_B_c (2S)

   Stephan Narison (LUPM, CNRS-Montpellier)🇫🇷

   We extract (for the first time) the correlated values of the running masses m_c and m_b from M_Bc using QCD Laplace sum rules (LSR) within stability criteria where pertubative (PT) expressions at N2LO and non-perturbative (NP) gluon condensates at LO are included. Allowing the values of m_{c,b}(m_{c,b}) to move inside the enlarged range of recent estimates from charmonium and bottomium sum rules (Table 1) obtained using similar stability criteria, wee deduce : m_c(m_c) = 1286(16) MeV and m_b(m_b) = 4208(8) MeV. Combined with previous estimates (Table 2), we deduce a tentative QCD Spectral Sum Rules (QSSR) average m_c(m_c) = 1266(6) MeV and m_b(m_b) = 4197(8) MeV, where the errors come from the precise determinations from J/psi and Upsilon sum rules. As a result, we present an improved prediction of f_B_c =371(17)MeV and the tentative upper bound f_B_c(2S)<139(6) MeV, which are useful for a further analysis of B_c-decays.

   hep-phhep-exhep-latPLB(2020)·35 citations
9. 09*

   Elliptic flow of identified particles in Pb-Pb collisions at $\sqrt{s_{NN}}=5.02$ TeV

   Er-Qin Wang🇨🇳 · Yin-Qun Ma🇨🇳 · Li-Na Gao🇨🇳 · San-Hong Fan🇨🇳

   In this paper, by using a Tsallis-Pareto-type function and the multisource thermal model, the elliptic flow coefficients of particles ${\pi }^{\pm }$, $K^{\pm }$, $p+\overline{p}$, \Lambda +\overline{% \Lambda }, and $K_S^0$ produced in Pb-Pb collisions at the center-of-mass energy of $\sqrt{s_{NN}}=5.02$ TeV are investigated. In the process of collisional evolution, because of geometric structure, pressure gradient, and thermal diffusion effects, deformation and translation occurred in the isotropic emission source, leading to anisotropy in the azimuth distribution of the final-state particles. Based on these dynamic factors, the dependence of elliptic flow on transverse momentum is described as well.

   hep-phnucl-thAdv.High Energy Phys.(2020)·1 citation
10. 10*

    A compact analytical approximation for a light sterile neutrino oscillation in matter

    Baobiao Yue🇨🇳 · Wei Li🇨🇳 · Jiajie Ling🇨🇳 · Fanrong Xu🇨🇳

    The existence of light sterile neutrinos is a long standing question for particle physics. Several experimental ``anomalies'' could be explained by introducing ~eV mass scaled light sterile neutrinos. Many experiments are actively hunting for such light sterile neutrinos through neutrino oscillation. For long baseline experiments, matter effect needs to be treated carefully for precise neutrino oscillation probability calculation. However, it is usually time-consuming or analytical complexity. In this manuscript we adopt the Jacobi-like method to diagonalize the Hermitian Hamiltonian matrix and derive analytically simplified neutrino oscillation probabilities for 3 (active) + 1 (sterile)-neutrino mixing for a constant matter density. These approximations can reach quite high numerical accuracy while keeping its analytical simplicity and fast computing speed. It would be useful for the current and future long baseline neutrino oscillation experiments.

    hep-phhep-exCPC(2020)·10 citations
11. 11*

    Bethe's Ansatz for Coulomb -Nuclear Interference Is Incompatible with Additive Eikonal

    Vladimir A. Petrov🇷🇺

    This is a proof that if the eikonal is, as usually assumed, additive in strong and electro-magnetic interactions then the application of the Bethe Ansatz for the full scattering amplitude leads to the strong interaction scattering amplitude with the ratio ( real/imaginary) independent on the transferred momentum $t$. Moreover, the unitarity condition makes the strong interaction amplitude vanishing. Thus, the Bethe form for the Coulomb-nuclear scattering amplitude and the same amplitude based on the additive eikonal are incompatible.

    hep-ph3 citations
12. 12*

    Decay behaviors of possible ${\Lambda }_{c\bar{c}}$ states in hadronic molecule pictures

    Chao-Wei Shen🇨🇳 · Jia-Jun Wu🇨🇳 · Bing-Song Zou🇨🇳

    In 2010, ${\Lambda }_{c\bar{c}}^{\ast }$ states were predicted as the strange number $S=-1$ partners of $N_{c\bar{c}}^{\ast }$, which are well known now as the $P_c$ states and observed experimentally by LHCb Collaboration. We analyze the decay behaviors of ${\Lambda }_{c\bar{c}}$ as S-wave hadronic molecules within the effective Lagrangian framework by a similar method, which has been applied on $P_c$ states successfully. With partial widths of possible decay channels calculated, we find that ${\Lambda }_{c\bar{c}}(4213)$ and ${\Lambda }_{c\bar{c}}(4403)$, which are formed as pseudoscalar meson baryon molecules, mainly decay to the ${\eta }_c\Lambda$ channel. For the two vector meson baryon molecule states, our results show that the total decay width with $J^P={\frac{1}{2}}^{-}$ is by one order of magnitude larger than that with $J^P={\frac{3}{2}}^{-}$. The decay patterns and relative decay ratios are very different for ${\Lambda }_{c\bar{c}}(4370)$ being a $D_s^{\ast -}{\Lambda }_c^{+}$ or ${\bar{D}}^{\ast }{\Xi }_c$ molecule state. The main decay channels of ${\Lambda }_{c\bar{c}}(4550)$ are ${\bar{D}}^{(\ast )}{\Xi }_c^{(\ast ,\prime )}$ because of the pseudoscalar meson exchange mechanism. In addition, ${\bar{D}}^{\ast }{\Xi }_c$ is the dominant decay channel of ${\Lambda }_{c\bar{c}}(4490)$ which is assumed as a $\bar{D}{\Xi }_c^{\ast }$ bound state. These decay patterns of the ${\Lambda }_{c\bar{c}}^{\ast }$ states would provide a guidance for their future experimental searches and help us to understand their internal structures.

    hep-phPRD(2019)·57 citations
13. 13*

    Neutron production induced by $\alpha$-decay with Geant4

    E. Mendoza🇪🇸 · D. Cano-Ott🇪🇸 · P. Romojaro🇪🇸 · V. Alcayne🇪🇸 · P. García Abia🇪🇸 · V. Pesudo🇪🇸 · L. Romero🇪🇸 · R. Santorelli🇪🇸

    Neutron production induced by ($\alpha$,n) reactions is important in various scenarios. One of the most relevant ones is related to underground dark matter experiments, where the neutrons produced by the $\alpha$-decay from radioactive contaminants in the detector materials can generate an irreducible background, limiting the sensitivity of the experiment. A precise estimate of the background due to these neutrons is crucial for the experiments currently taking data and for the design of the next generation detectors. In this work, we prove that Geant4 can be used to calculate neutron yields and energy spectra induced by $\alpha$-decay. These neutrons are produced according to the information compiled in data libraries originally written in the ENDF-6 format. In this article we also review the different databases available, showing the differences and similarities among them. Finally, we compare several Geant4 neutron production yields and spectra with experimental data and other codes.

    hep-phnucl-thNucl.Instrum.Meth.A(2020)·34 citations
14. 14*

    Sensitivity on Anomalous Neutral Triple Gauge Couplings via $ZZ$ Production at FCC-hh

    A. Yilmaz🇹🇷 · A. Senol🇹🇷 · H. Denizli🇹🇷 · I. Turk Cakir🇹🇷 · O. Cakir🇹🇷

    We study the sensitivity of anomalous neutral triple gauge couplings ($aNTGC$) via $pp\to ZZ$ production in the 4$\ell$ channel at 100 TeV centre of mass energy of future circular hadron collider, \verb"FCC-hh". The analysis including the realistic detector effects is performed in the mode where both Z bosons decay into same flavor, oppositely charged lepton pairs. The sensitivities to the charge-parity (CP)-conserving $C_{\tilde{B}W}/{\Lambda }^4$ and CP-violating $C_{WW}/{\Lambda }^4$, $C_{BW}/{\Lambda }^4$ and $C_{BB}/{\Lambda }^4$ couplings obtained at 95\% Confidence Level (C.L.) using the invariant mass distribution of 4$\ell$ system reconstructing the leading and sub-leading Z boson candidates are $[-0.117,+0.117]$, $[-0.293,+0.292]$, $[-0.380,+0.379]$, and $[-0.138,+0.138]$ in the unit of TeV${}^{-4}$, respectively.

    hep-phEPJC(2020)·15 citations
15. 15*

    Transverse momentum and pseudorapidity dependence of particle production in Xe-Xe collision at 5.44 TeV

    Zhang-Li Guo🇨🇳 · Bao-Chun Li🇨🇳 · Hong-Wei Dong🇨🇳

    Through the collision-system configuration, the Tsallis statistics is combined with a multisource thermal model. The improved model is used to investigate the transverse momentum and pseudorapidity of particles produced in Xe-Xe collisions at 5.44 TeV. We discuss detailedly the thermodynamic properties, which are taken from the transverse momentum distributions of pion, kaon and proton for different centralities. The pseudorapidity spectra of charged particles for different centralities are described consistently in the model. And, the model result can estimate intuitively the longitudinal configuration of the collision system. PACS numbers: 13.85.-t, 14.40.-n, 12.40.Ee

    hep-phnucl-thAdv.High Energy Phys.(2020)·1 citation
16. 16*

    A two loop induced neutrino mass model with modular $A_4$ symmetry

    Takaaki Nomura🇰🇷 · Hiroshi Okada🇰🇷

    We propose a model with radiatively induced neutrino mass at two-loop level, applying modular $A_4$ symmetry. The neutrino mass matrix is formulated where the structure of associated couplings are restricted by the symmetry. Then we show several predictions in the lepton sector, satisfying lepton flavor violations as well as neutrino oscillation data. We also discuss muon anomalous magnetic moment and briefly comment on dark matter candidate.

    hep-phNPB(2021)·122 citations
17. 17*

    Constraints for nuclear PDFs from the LHCb D-meson data

    Kari J. Eskola🇫🇮 · Ilkka Helenius🇫🇮 · Petja Paakkinen🇫🇮 · Hannu Paukkunen🇫🇮

    We quantify the impact of LHCb D-meson measurements at $\sqrt{s}=5\mathrm{TeV}$ on the EPPS16 and nCTEQ15 nuclear PDFs. In our study, the theoretical description of D-meson production is based on the recently developed SACOT-$m_{\mathrm{T}}$ variant of the general-mass variable-flavour-number formalism, and the impact on PDFs is estimated via reweighting methods. We pay special attention on the theoretical uncertainties known to us, and are led to exclude the $p_{\mathrm{T}}<3\mathrm{GeV}$ region from our main analysis. The LHCb data can be accommodated well within EPPS16 and nCTEQ15, and the data provide stringent constraints on the gluons in the shadowing/antishadowing regions. No evidence of non-linear effects beyond standard DGLAP evolution is found even if the full kinematic region down to zero $p_{\mathrm{T}}$ is considered.

    hep-phPoS(2019)·0 citations
18. 18*

    Light axial-vector and vector resonances $X(2100)$ and $X(2239)$

    K. Azizi🇮🇷 · S. S. Agaev🇦🇿 · H. Sundu🇹🇷

    We study features of the resonances $X(2100)$ and $X(2239)$ by treating them as the axial-vector and vector tetraquarks with the quark content $ss\overline{s}\overline{s}$, respectively. The spectroscopic parameters of these exotic mesons are calculated in the framework of the QCD two-point sum rule method. Obtained prediction for the mass $m=(2067\pm 84)\mathrm{MeV}$ of the axial-vector state is in excellent agreement with the mass of the structure $X(2100)$ recently observed by the BESIII Collaboration in the decay $J/\psi \to \varphi \eta {\eta }^{\prime }$ as the resonance in the $\varphi {\eta }^{\prime }$ mass spectrum. We explore also the $S$-wave decays $X(2100)\to \varphi {\eta }^{\prime }$ and $X(2100)\to \varphi \eta$ using the QCD light-cone sum rule approach and technical methods of the soft-meson approximation. The width of the axial-vector tetraquark, $\Gamma =(130.2\pm 30.1)\mathrm{MeV}$, saturated by these two decays is comparable with the measured full width of the resonance $X(2100)$. Our prediction for the vector $ss\overline{s}\overline{s}$ tetraquark's mass $\tilde{m}=(2283\pm 114)\mathrm{MeV}$ is consistent with the experimental result $2239.2\pm 7.1\pm 11.3\mathrm{MeV}$ of the BESIII Collaboration for the mass of the resonance $X(2239)$.

    hep-phhep-exhep-latNPB(2019)·18 citations
19. 19*

    Baryogenesis and helical magnetogenesis from the electroweak transition of the minimal Standard Model

    Dmitri Kharzeev🇺🇸 · Edward Shuryak🇺🇸 · Ismail Zahed🇺🇸

    We start by considering the production rates of sphalerons with different size $\rho$ in the symmetric phase, $T>T_{EW}$. At small $\rho$, the distribution is cut off by the growing mass $M\sim 1/\rho$, and at large $\rho$ by the magnetic screening mass. In the broken phase, $T<T_{EW}$ the scale is set by the Higgs VEV $v(T)$. We introduce the concept of "Sphaleron freezeout" whereby the sphaleron production rate matches the Hubble Universe expansion rate. At freezeout the sphalerons are out of equilibrium. Sphaleron explosions generate sound and even gravity waves, when nonzero Weinberg angle make them non-spherical. We revisit CP violation during the sphaleron explosions. We assess its magnitude using the Standard Model CKM quark matrix, first for nonzero and then zero Dirac eigenstates. We find that its magnitude is maximal at the sphaleron freezeout condition with $T\approx 130GeV$. We proceed to estimate the amount of CP violation needed to generate the observed magnitude of baryon asymmetry of Universe. The result is about an order of magnitude below our CKM-based estimates. We also relate the baryon asymmetry to the generation of $U(1)$ magnetic chirality, which is expected to be conserved and perhaps visible in polarized intergalactic magnetic fields.

    hep-phPRD(2020)·19 citations
20. 20*

    Long-lived TeV-scale right-handed neutrino production at the LHC in gauged $U(1{)}_X$ model

    Arindam Das🇯🇵 · P. S. Bhupal Dev🇺🇸 · Nobuchika Okada🇺🇸

    A gauged $U(1{)}_X$ extension of the Standard Model is a simple and consistent framework to naturally incorporate three right-handed neutrinos (RHNs) for generating the observed light neutrino masses and mixing by the type-I seesaw mechanism. We examine the collider testability of the $U(1{)}_X$ model, both in its minimal form with the conventional charges, as well as with an alternative charge assignment, via the resonant production of the $U(1{)}_X$ gauge boson ($Z^{\prime }$) and its subsequent decay into a pair of RHNs. We first derive an updated upper limit on the new gauge coupling $g_X$ as a function of the $Z^{\prime }$-boson mass from the latest LHC dilepton searches. Then we identify the maximum possible cross section for the RHN pair-production under these constraints. Finally, we investigate the possibility of having one of the RHNs long-lived, even for a TeV-scale mass. Employing the general parametrization for the light neutrino mass matrix to reproduce the observed neutrino oscillation data, we perform a parameter scan and find a simple formula for the maximum RHN lifetime as a function of the lightest neutrino mass eigenvalue ($m_{\mathrm{lightest}}$). We find that for $m_{\mathrm{lightest}}\lesssim 10^{-5}$ eV, one of the RHNs in the minimal $U(1{)}_X$ scenario can be long-lived with a displaced-vertex signature which can be searched for at the LHC and/or with a dedicated long-lived particle detector, such as MATHUSLA. In other words, once a long-lived RHN is observed, we can set an upper bound on the lightest neutrino mass in this model.

    hep-phhep-exPLB(2019)·81 citations
21. 21*

    Reconstructing Non-standard Cosmologies with Dark Matter

    Paola Arias🇨🇱 · Nicolás Bernal🇨🇴 · Alan Herrera🇨🇴 · Carlos Maldonado🇨🇱

    Once dark matter has been discovered and its particle physics properties have been determined, a crucial question rises concerning how it was produced in the early Universe. If its thermally averaged annihilation cross section is in the ballpark of few$\times 10^{-26}$ cm${}^3$/s, the WIMP mechanism in the standard cosmological scenario (i.e. radiation dominated Universe) will be highly favored. If this is not the case one can either consider an alternative production mechanism, or a non-standard cosmology. Here we study the dark matter production in scenarios with a non-standard expansion history. Additionally, we reconstruct the possible non-standard cosmologies that could make the WIMP mechanism viable.

    hep-phJCAP(2019)·69 citations
22. 22*

    An Effective Theory of Quarkonia in QCD Matter

    Yiannis Makris🇺🇸 · Ivan Vitev🇺🇸

    For heavy quarkonia of moderate energy, we generalize the relevant successful theory, non-relativistic Quantum Chromodynamics (NRQCD), to include interactions in nuclear matter. The new resulting theory, NRQCD with Glauber gluons, provides for the first time a universal microscopic description of the interaction of heavy quarkonia with a strongly interacting medium, consistently applicable to a range of phases, such as cold nuclear matter, dense hadron gas, and quark-gluon plasma. The effective field theory we present in this work is derived from first principles and is an important step forward in understanding the common trends in proton-nucleus and nucleus-nucleus data on quarkonium suppression.

    hep-phnucl-thJHEP(2019)·30 citations
23. 23*

    Searching for Dark Matter in the Galactic Halo with a Wide Field of View TeV Gamma-ray Observatory in the Southern Hemisphere

    Aion Viana🇧🇷 · Harm Schoorlemmer🇩🇪 · Andrea Albert🇺🇸 · Vitor de Souza🇧🇷 · J. Patrick Harding🇺🇸 · Jim Hinton🇩🇪

    Despite mounting evidence that dark matter (DM) exists in the Universe, its fundamental nature remains unknown. We present sensitivity estimates to detect DM particles with a future very-high-energy ($\gtrsim$ TeV) wide field-of-view gamma-ray observatory in the Southern Hemisphere. This observatory would search for gamma rays from the annihilation or decay of DM particles in the Galactic halo. With a wide field of view, both the Galactic Center and a large fraction of the Galactic halo will be detectable with unprecedented sensitivity to DM in the mass range of $\sim$500 GeV to $\sim$2 PeV. These results, combined with those from other present and future gamma-ray observatories, will likely probe the thermal relic annihilation cross section of Weakly Interacting Massive Particles for all masses from $\sim$80 TeV down to the GeV range in most annihilation channels.

    ↳ astro-ph.HEhep-exhep-phJCAP(2019)·50 citations
24. 24*

    Charge-dependent pair correlations relative to a third particle in $p$+Au and $d$+Au collisions at RHIC

    STAR collaboration

    Quark interactions with topological gluon configurations can induce chirality imbalance and local parity violation in quantum chromodynamics. This can lead to electric charge separation along the strong magnetic field in relativistic heavy-ion collisions -- the chiral magnetic effect (CME). We report measurements by the STAR collaboration of a CME-sensitive observable in $p$+Au and $d$+Au collisions at 200 GeV, where the CME is not expected, using charge-dependent pair correlations relative to a third particle. We observe strong charge-dependent correlations similar to those measured in heavy-ion collisions. This bears important implications for the interpretation of the heavy-ion data.

    ↳ nucl-exhep-exhep-phnucl-thPLB(2019)·56 citations
25. 25*

    Scale independent $R^2$ inflation

    Pedro G. Ferreira🇬🇧 · Christopher T. Hill🇺🇸 · Johannes Noller🇨🇭 · Graham G. Ross🇬🇧

    Weyl (scale) invariant theories of scalars and gravity can generate all mass scales spontaneously. In this paper we study a particularly simple version -- scale invariant $R^2$ gravity -- and show that, during an inflationary period, it leads to fluctuations which, for a particular parameter choice, are almost indistinguishable from normal $R^2$ inflation. Current observations place tight constraints on the primary coupling constant of this theory and predict a tensor to scalar ratio, $0.0033>r>0.0026$, which is testable with the next generation of cosmic microwave background experiments.

    ↳ gr-qcastro-ph.COhep-phhep-thPRD(2019)·59 citations
26. 26*

    Area Law Saturation of Entropy Bound from Perturbative Unitarity in Renormalizable Theories

    Gia Dvali🇩🇪

    We study the quantum information storage capacity of solitons and baryons in renormalizable quantum field theories that do not include gravity. We observe that a 't Hooft-Polyakov magnetic monopole saturates the Bekenstein bound on information when the theory saturates the bound on perturbative unitarity. In this very limit the monopole entropy assumes the form of an area-law, strikingly similar to a black hole entropy in gravity. The phenomenon appears universal and takes place for other solitons and non-perturbative objects. We observe the same behaviour of entropy of a baryon in QCD with large number of colors. These observations indicate that the area-law form of the entropy bound extends beyond gravity and is deeply rooted in concepts of weak coupling and perturbative unitarity. One provoked idea is that confinement in QCD may be understood as a prevention mechanism against violation of Bekenstein entropy bound by colored states.

    ↳ hep-thhep-phFortsch.Phys.(2021)·45 citations
27. 27*

    Sensitivity of the excitation functions of collective flow to relativistic scalar and vector meson interactions in the relativistic quantum molecular dynamics model RQMD.RMF

    Yasushi Nara🇯🇵 · Horst Stoecker🇩🇪

    Relativistic quantum molecular dynamics with scalar and vector interactions based on the relativistic mean meson field theory, RQMD.RMF, is developed.It is implemented into the microscopic transport code JAM.The sensitivity of the directed and of the elliptic proton flow in high energy heavy-ion collisions on the stiffness of the RMF equation of state (EoS) is examined. These new calculations are compared to experimental data at mid-central Au + Au collisions in the beam energy range $2.5<\sqrt{s_{NN}}<20$ GeV. This new RQMD model with the relativistic mean field scalar and vector meson interactions does describe consistently, with one RMF parameter set,the beam energy dependence of both the directed flow and the elliptic flow,from SIS18 to AGS and RHIC BES-II energies, $\sqrt{s_{NN}}<10$ GeV.There are different sensitivities of these different kinds of flow to the EoS: elliptic flow is most sensitive to the nuclear incompressibility constant,at the moderate beam energies $\sqrt{s_{NN}}<3$ GeV,whereas the directed flow is most sensitive to the effective baryon mass at saturation density at $3<\sqrt{s_{NN}}<5$ GeV. Matters abruptly change in the next higher energy range,$\sqrt{s_{NN}}\gtrsim 10-20$ GeV:the directed flow data show a double change of sign of the slope of $v_1$, inverting twice in this energy range,in sudden contradiction to the RQMD.RMF calculation for a monotonous, stiff EoS. This surprising oscillating behavior,a double change of sign of the $v_1$ slope, points to the appearance of a hitherto unknown first-order phase transition in excited QCD matter at high baryon densities in mid-central Au + Au collisions.

    ↳ nucl-thhep-phnucl-exPRC(2019)·42 citations
28. 28*

    Study of the pseudoscalar glueball in $J/\psi$ radiative decays

    Long-Cheng Gui🇨🇳 · Jia-Mei Dong🇨🇳 · Ying Chen🇨🇳 · Yi-Bo Yang🇨🇳

    We aim to explore the production rate of the pseudoscalar glueball in $J/\psi$ radiative decay by lattice QCD in quenched approximation. The calculation is performed on three anisotropic lattices with the spatial lattice spacing ranging from 0.222(2) fm to 0.110(1) fm. As a calibration of some systematical uncertainties, we first extract the $M1$ form factor $\hat{V}(0)$ of the process $J/\psi \to \gamma {\eta }_c$ and get the result $\hat{V}(0)=1.933(41)$ in the continuum limit, which gives the partial width $\Gamma (J/\psi \to \gamma {\eta }_c)=2.47(11)$ keV. These results are in agreement with that of previous lattice studies. As for the pseudoscalar glueball $G_{0^{-+}}$, its mass is derived to be $2.395(14)$ GeV, and the form factor $\hat{V}(0)$ of the process $J/\psi \to \gamma G_{0^{-+}}$ is determined to be $\hat{V}(0)=0.0246(43)$ after continuum extrapolation. Finally, the production rate of the pseudoscalar glueball is predicted to be $2.31(90)\times 10^{-4}$, which is much smaller than that of conventional light $q\bar{q}$ $\eta$ states. After the subtraction of the phase space factor, the couplings of $J/\psi X\gamma$ are similar where $X$ stands for $\eta$ states and the pseudoscalar glueball. Possibly, the $U_A(1)$ anomaly plays an important role for the large couplings of gluons to the flavor singlet $\eta$ states in $J/\psi$ radiative decays.

    ↳ hep-lathep-exhep-phPRD(2019)·63 citations
29. 29*

    Signatures of relic quantum nonequilibrium

    Nicolas G. Underwood🇺🇸

    [Shortened Abstract:] This thesis explores the possibility that quantum probabilities arose thermodynamically. A chief concern is the detection of primordial `quantum nonequilibrium', since this is observably distinct from textbook quantum physics. Chapters 2, 3, 4, and 5 are adaptations of references [1,2,3], and [4] respectively. Chapter 2 proposes (information) entropy conservation as a minimal requirement for a theory to feature classical-style thermodynamic relaxation. The resulting structure is dubbed `the iRelax framework'. Both classical mechanics and de Broglie-Bohm quantum theory are shown to be special cases. Indications for a possible extension or unification of de Broglie-Bohm theory are briefly highlighted. Chapter 3 examines ways in which quantum relaxation may be prevented. The method of the drift-field is introduced. A systematic treatment of nodes is given. A category of quantum states is found for which relaxation is significantly impeded, and may not complete at all. Chapters 4 and 5 consider the possibility that primordial quantum nonequilibrium may be conserved in the statistics of a species of relic cosmological particle. Necessary factors for this to be the case are discussed and illustrative scenarios are given both in terms of nonequilibrium particles created by inflaton decay, as well as relic vacuum modes for species that decoupled close to the Planck temperature. The search for so-called `smoking-gun' spectral lines created by dark matter decay or annihilation is argued to be a particularly promising setting for the detection of quantum nonequilibrium. Unintuitive spectral effects relating to the contextuality of quantum measurements are described. If such a suspected source of quantum nonequilibrium were found, its subjection to a specifically quantum mechanical test would confirm or deny the presence of the quantum nonequilibrium conclusively.

    ↳ quant-phastro-ph.COhep-ph3 citations

* Reconstructed cohort: no mailing for this day survives in the archive. Papers are grouped by their submission times and arXiv's announcement cut-off, assuming announcement without delay; positions follow identifier order. Validated at ~91% exact-day agreement against the archived era.