High Energy Physics - Phenomenology (hep-ph)

Abstract: We propose a minimal setup that realises dynamical inflection point inflation, and, using the same field content, generates neutrino masses, a baryon asymmetry of the universe, and dark matter. A dark $SU(2)_D$ gauge sector with a dark scalar doublet playing the role of inflaton is considered along with several doublet and singlet fermions sufficient to realise multiple inflection points in the inflaton potential. The singlet fermions couple to SM leptons and generate neutrino masses via the inverse seesaw mechanism. Those fermions also decay asymmetrically and out of equilibrium, generating a baryon asymmetry via leptogenesis. Some of the fermion doublets are dark matter, and they are produced via freeze-in annihilation of the same fermions that generate the lepton asymmetry. Reheating, leptogenesis, and dark matter are all at the TeV scale.

Abstract: In this paper, spectra of the quarkonium states has been studied using the conditions temperature, chemical potential and the magnetic field. Here our main focus is to study the effect of strong magnetic field on the quarkonium properties. The binding energies and the dissociation temperature for the ground and the first excited states of the charmonium and bottomonium in the presence of strong magnetic field at chemical potential \mu = 500 MeV has been studied. Here we use quasiparticle (QP) Debye mass depending upon temperature, magnetic field and chemical potential obtained from the quasiparticle approach. The Debye mass strongly increases at different values of temperature and magnetic field. The binding energy decreases with increase in the temperature at different magnetic field eB= 0.3, 0.5, and 0.7 GeV2 and also decreases with magnetic field at different at T=200,300 and 400 MeV for the J/\psi, \psi, \upsilon, and \upsilon prime states of the quarkonia. The dissociation temperature of the quarkonium states falls with the increasing values of the magnetic field at critical temperature Tc =197 MeV

Abstract: I will review the main chiral transport phemomena arising in systems made up of (almost) massless fermions associated to the quantum chiral anomaly. These quantum effects might have relevant implications in compact stars, and I will review some relevant works that reveal so. I will also show how a conservation law that has the same form of the chiral anomaly also emerge in perfect classical fluids, which expresses a conservation law of magnetic, fluid and mixed helicities for isentropic fluids, and why this should also be relevant in compact stars.

Abstract: The chiral symmetry is explicitly and spontaneously broken in a strongly interacting massive fermionic system. We study the chiral symmetry restoration in massive four-fermion interaction models with increasing temperature and chemical potential. At high temperature and large chemical potential, we find the boundaries where the spontaneously broken chiral symmetry can be fully restored in the massive Gross--Neveu model. We call the phenomenon super restoration. The phase boundary is obtained analytically and numerically. In the massive Nambu--Jona-Lasinio model, it was found that whether super restoration occurs depends on regularizations. We also evaluate the behavior of the dynamical mass and show the super restoration boundaries on the ordinary phase diagrams.

Abstract: As dense and hot bodies with a well-understood equation of state, white dwarfs offer a unique opportunity to investigate new physics. In this paper, we examine the role of dark sectors, which are extensions of the Standard Model of particle physics that are not directly observable, in the cooling process of white dwarfs. Specifically, we examine the role of a dark photon, within the framework of a three-portal Model, in enhancing the neutrino emission during the cooling process of white dwarfs. We compare this scenario to the energy release predicted by the Standard Model. By analyzing the parameter space of dark sectors, our study aims to identify regions that could lead to significant deviations from the expected energy release of white dwarfs.

Abstract: The elastic pion-proton and pion-pion scattering are studied in a holographic QCD model, focusing on the Regge regime. Taking into account the Pomeron and Reggeon exchange, which are described by the Reggeized $2^{++}$ glueball and vector meson propagator respectively, the total and differential cross sections are calculated. The adjustable parameters involved in the model are determined with the experimental data of the pion-proton total cross sections. The differential cross sections can be predicted without any additional parameters, and it is shown that our predictions are consistent with the data. The energy dependence of the Pomeron and Reggeon contribution is also discussed.

Abstract: In light of the fermionic dark matter absorption on electron target that can be observed by direct detection experiments, we study its complementary searches at the future $e^+ e^-$ colliders such as CEPC, FCC-ee, ILC, and CLIC. Two typical processes, the mono-photon and electron-positron pair production associated with missing energy, can serve the purpose. While the mono-photon search prevails at CEPC, FCC-ee, and ILC, the $e^+ e^-E_{T}^{\rm miss}$ channel has more significant contributions at CLIC with much higher collision energy $\sqrt s$. The beam polarizations can help further suppressing the SM backgrounds to enhance the signal significance while differential cross sections can distinguish the Lorentz structure of various effective operators. The combined sensitivity can reach well above 1 TeV at CEPC/FCC-ee and ILC while it further touches 30 TeV at CLIC. Comparing with the updated results from the dark matter direct detection experiments (XENON1T, PandaX-II, PandaX-4T, LZ, and XENONnT), astrophysical $X/\gamma$ observations, and cosmological constraints, the collider searches can not just provide better sensitivity for light dark matter mass but also scan much wider mass range.

Abstract: We consider the effect of gluon condensation on the holographic entanglement entropy, which can be regarded as an order parameter of deconfinement phase transition, in a holographic model at zero and finite temperature. At zero temperature, it is found that phase transition can occur at critical length for small gluon condensation. With the increase of gluon condensation, the critical length becomes small which means the phase transition is easy to occur. The difference of entanglement entropy between the connected and disconnected surfaces is always negative at large gluon condensation, which indicates no phase transition can occur in the deconfined phase as the subsystem size varies. These results show that the gluon condensation is related to the phase transition and contributes to deconfinement. At finite temperature, we can see that the difference of the entanglement entropy is also always negative and the system is always deconfined for vanishing and non-vanishing gluon condensation in this model. These results confirm that the difference of entanglement entropy is a useful probe to detect whether a system is in the confinement or deconfinement phase.

Abstract: One of the main goals of future electron-ion colliders is to improve our understanding of the structure of hadrons. In this letter, we study the exclusive $\eta_c$ production by $\gamma^{*} \gamma$ interactions in $eA$ collisions and demonstrate that future experimental analysis of this process can be used to improve the description of the $\eta_c$ transition form factor. The rapidity, transverse momentum and photon virtuality distributions are estimated considering the energy and target configurations expected to be present at the EIC, EicC and LHeC and assuming different predictions for the light-front wave function of the $\eta_c$ meson. Our results indicate that the electron-ion colliders can be considered an alternative to providing supplementary data to those obtained in $e^- e^+$ colliders.

Abstract: We studied the effect of momentum space anisotropy on heavy quarkonium states using an extended magnetized effective fugacity quasiparticle model (EQPM). Both the real and imaginary part of the potential has been modified through the dielectric function by including the anisotropic parameter $\xi$. The real part of the medium modified potential becomes more attractive in the presence of the anisotropy and constant magnetic field. The binding energy of the 1S, 2S, and 1P quarkonium states including anisotropy effects for both the oblate and the isotropic case were studied. We find that the binding energy of quarkonium states becomes stronger in the presence of anisotropy. However, the magnetic field is found to reduce the binding energy. The thermal width of the charmonium and bottomonium 1S states have been studied at constant magnetic field eB = 0.3 GeV2 for isotropic and prolate cases. The effect of magnetic field on the mass spectra of the 1P state for the oblate case was also examined. The dissociation temperature for the 1S, 2S, and 1P charmonium and bottomonium have been determined to be higher for the oblate case with respect to the isotropic case

Abstract: Generalized symmetries (also known as categorical symmetries) is a newly developing technique for studying quantum field theories. It has given us new insights into the structure of QFT and many new powerful tools that can be applied to the study of particle phenomenology. In these notes we give an exposition to the topic of generalized/categorical symmetries for high energy phenomenologists although the topics covered may be useful to the broader physics community. Here we describe generalized symmetries without the use of category theory and pay particular attention to the introduction of discrete symmetries and their gauging.

Abstract: Various supersymmetric (SUSY) scenarios predict a sub-GeV neutralino decaying into a single photon and an invisible state. This signature has recently been studied in a number of intensity frontier experiments, finding constraints complementary to the usual collider searches. In this work, we study the prospects of searches for long-lived neutralinos coupled to an ALPino or gravitino, where each can act as the lightest SUSY particle (LSP). In addition to the neutralino decays into a LSP and a photon, we also consider three-body decays into a pair of charged leptons, and signatures related to scattering with electrons and secondary neutralino production. For both models, we find that the searches at FASER2 will allow to overcome the current bounds, while SHIP will extend these limits by more than an order of magnitude in the value of the coupling constant.