Mon·Apr 26, 2021Monday·April 26, 2021

1. 01*

   Collisional flavor instabilities of supernova neutrinos

   Lucas Johns🇺🇸

   A lingering mystery in core-collapse supernova theory is how collective neutrino oscillations affect the dynamics. All previously identified flavor instabilities, some of which might make the effects considerable, are essentially collisionless phenomena. Here it is shown that collisional instabilities exist as well. They are associated with asymmetries between the neutrino and antineutrino interaction rates, are possibly prevalent deep inside supernovae, and pose an unusual instance of decoherent interactions with a thermal environment causing the sustained growth of quantum coherence.

   hep-phastro-ph.HEPRL(2023)·123 citations
2. 02*

   Dilepton production from magnetized quark matter with an anomalous magnetic moment of the quarks using a three-flavor PNJL model

   Nilanjan Chaudhuri🇮🇳 · Snigdha Ghosh🇮🇳 · Sourav Sarkar🇮🇳 · Pradip Roy🇮🇳

   Dilepton production from hot, dense and magnetized quark matter is studied using the three-flavor Polyakov loop extended Nambu--Jona-Lasinio (PNJL) model in which the anomalous magnetic moment (AMM) of the quarks is also taken into consideration. This is done by first evaluating the thermo-magnetic spectral function of the vector current correlator employing the real time formalism of finite temperature field theory and the Schwinger proper time formalism. The constituent quark mass which goes as an input in the expression of the dilepton production rate (DPR), has been calculated using the three-flavor PNJL model employing Pauli-Villiars (PV) regularization. The obtained constituent quark mass being strongly dependent on the temperature, density, magnetic field and AMM of the quarks, captures the effect of `strong' interactions specifically around the (pseudo) chiral and confinement-deconfinement phase transition regions. The analytic structure of the spectral function in the complex energy plane has been analyzed in detail and a non-trivial Landau cut is found in the physical kinematic domains resulting from the scattering of the Landau quantized quark/antiquark with the photon which is purely a finite magnetic field effect. Due to the emergence of the Landau cut along with the usual unitary cut, the DPR is found to be largely enhanced in the low invariant mass region. Owing to the magnetic field and AMM dependence of the thresholds of these cuts, we find that the kinematically forbidden gap between the Unitary and Landau cuts vanishes at sufficiently high temperature, density and magnetic field leading to the generation of a continuous spectrum of dilepton emission over the whole invariant mass region. In order to see the effects of strangeness and confinement-deconfinement, the rates are compared with the three-flavor NJL and the two-flavor NJL and PNJL models.

   hep-phnucl-thPRD(2021)·35 citations
3. 03*

   Bounded-from-below conditions for $A_4$-symmetric 3HDM

   N. Buskin🇷🇺 · Igor P. Ivanov🇨🇳

   Deriving necessary and sufficient conditions for a scalar potential to be bounded from below (BFB) is a difficult task beyond the simplest cases. Recently, a set of BFB conditions was proposed for the $A_4$-invariant three-Higgs-doublet model (3HDM). However, that set of conditions relied on numerical scan, and a complete analytic proof was lacking. Here, we fill this gap. We prove that the conjectured BFB conditions are indeed necessary and sufficient within the neutral Higgs subspace. We bypass technically challenging direct algebraic computations with a novel technique that relies on an auxiliary function, which is related to the Higgs potential but which is easier to analyze. This technique may finally be sufficient to tackle the more involved case of the original Weinberg's 3HDM model.

   hep-phmath-phmath.MPJ.Phys.A(2021)·13 citations
4. 04*

   Constraining CP4 3HDM with top quark decays

   Igor P. Ivanov🇨🇳 · Semyon A. Obodenko🇷🇺

   CP4 3HDM is a unique three-Higgs-doublet model equipped with a higher-order CP symmetry in the scalar and Yukawa sector. Based on a single assumption (the minimal model with a CP-symmetry of order 4 and no accidental symmetry), it leads to a remarkable correlation between its scalar and Yukawa sectors, which echoes in its phenomenology. A recent scan of the parameter space of CP4 3HDM under the assumption of scalar alignment identified a few dozens of points which passed many flavour constraints. In the present work we show, however, that almost all of these points are now ruled out by the recent LHC searches of $t\to H^{+}b$ with subsequent hadronic decays of $H^{+}$. Apart from a few points with charged Higgses heavier than the top quark, only one point survives all the checks, the model with an exotic, non-2HDM-like generation pattern of $H^{+}$ couplings with quarks. One can expect many more points with exotic $H^{+}$ couplings to quarks if the scalar alignment assumption is relaxed.

   hep-phUniverse(2021)·16 citations
5. 05*

   Skyrmions in a magnetic field and ${\pi }^0$ domain wall formation in dense nuclear matter

   Shi Chen🇯🇵 · Kenji Fukushima🇯🇵 · Zebin Qiu🇯🇵

   We elucidate magnetic effects in the skyrmion system to probe into the dense nuclear matter. We find a deformed ${\pi }^0$ dipole structure of a baryon induced by a magnetic field. We then extend our scope to stacked Skyrme crystal layers to scrutinize phases of magnetized nuclear matter. We observe a quantized magnetic flux and identify a phase transition from a crystalline state to a ${\pi }^0$ domain wall corresponding to a topological transmutation from ${\pi }_3(S^3)$ to ${\pi }_1(S^1)$. We establish the phase diagram, which could be explored also in analogous systems with two-component Bose-Einstein condensates.

   hep-phhep-thnucl-thPRD(2022)·32 citations
6. 06*

   Dark matter and the early Universe: a review

   A. Arbey🇫🇷 · F. Mahmoudi🇫🇷

   Dark matter represents currently an outstanding problem in both cosmology and particle physics. In this review we discuss the possible explanations for dark matter and the experimental observables which can eventually lead to the discovery of dark matter and its nature, and demonstrate the close interplay between the cosmological properties of the early Universe and the observables used to constrain dark matter models in the context of new physics beyond the Standard Model.

   hep-phastro-ph.COPPNP(2021)·422 citations
7. 07*

   CP violating dark photon kinetic mixing and type-III seesaw model

   Yu Cheng🇨🇳 · Xiao-Gang He🇨🇳 · Michael J. Ramsey-Musolf🇨🇳 · Jin Sun🇨🇳

   The hypothetical dark photon portal connecting the visible and dark sectors of the Universe has received considerable attention in recent years, with a focus on CP-conserving kinetic mixing between the Standard Model (SM) hypercharge gauge boson and a new U(1)${}_X$ gauge boson. In the effective field theory context, one may write down non-renormalizable CP-violating kinetic mixing interactions involving the $X$ and SU(2)${}_L$ gauge bosons. We construct for the first time a renormalizable model for CP-violating kinetic mixing that induces CP-violating non-Abelian kinetic mixing at mass dimension five. The model grows out of the type-III seesaw model, with the lepton triplets containing right-handed neutrinos playing a crucial role in making the model renormalizable and providing a bridge to the origin of neutrino mass. This scenario also accommodates electron electric dipole moments (EDM) as large as current experimental bound, making future EDM searches an important probe of this scenario.

   hep-phPRD(2022)·14 citations
8. 08*

   Experimental signatures of a new dark matter WIMP

   Reagan Thornberry🇺🇸 · Maxwell Throm🇺🇸 · Gabriel Frohaug🇺🇸 · John Killough🇺🇸 · Dylan Blend🇺🇸 · Michael Erickson🇺🇸 · Brian Sun🇺🇸 · Brett Bays🇺🇸 · Roland E. Allen🇺🇸

   The WIMP proposed here yields the observed abundance of dark matter, and is consistent with the current limits from direct detection, indirect detection, and collider experiments, if its mass is $\sim 72$ GeV/$c^2$. It is also consistent with analyses of the gamma rays observed by Fermi-LAT from the Galactic center (and other sources), and of the antiprotons observed by AMS-02, in which the excesses are attributed to dark matter annihilation. These successes are shared by the inert doublet model (IDM), but the phenomenology is very different: The dark matter candidate of the IDM has first-order gauge couplings to other new particles, whereas the present candidate does not. In addition to indirect detection through annihilation products, it appears that the present particle can be observed in the most sensitive direct-detection and collider experiments currently being planned.

   hep-phEPL(2021)·9 citations
9. 09*

   Composite Flavon-Higgs Models

   Yi Chung🇺🇸

   We consider a composite Higgs model based on the $SU(6)/Sp(6)$ coset, where an $U(1)$ subgroup of $Sp(6)$ is identified as the flavor symmetry. A complex scalar field $s$, which is a pseudo-Nambu-Goldstone boson of the broken symmetry, carries a flavor charge and plays the role of a flavon field. The $U(1{)}_F$ flavor symmetry is then broken by a VEV of the flavon field, which leads to a small parameter and generates the mass hierarchy between the top and bottom quarks. A light flavon below the TeV scale can be naturally introduced, which provides a fully testable model for the origin of flavor hierarchy. A light flavon also leads to substantial flavor changing neutral currents, which are strongly constrained by the flavor precision tests. The direct search of additional scalar bosons can also be conducted in HL-LHC and future hadron colliders.

   hep-phPRD(2021)·7 citations
10. 10*

    Novel observables for exploring QCD collective evolution and quantum entanglement within individual jets

    Austin Baty🇺🇸 · Parker Gardner🇺🇸 · Wei Li🇺🇸

    We postulate that non-perturbative QCD effects occurring during parton fragmentation can result in collective effects of a multi-parton system, reminiscent of those observed in high-energy hadronic or nuclear interactions with large final-state particle multiplicity. Proton-proton collisions at the Large Hadron Collider showed surprising signatures of a strongly interacting, thermalized quark-gluon plasma, which was thought only to form in collisions of large nuclear systems. Another puzzle observed earlier in $e^{+}{e}^{-}$ collisions is that production yields of various hadron species appear to follow a thermal-like distribution with a common temperature. We propose searches for thermal and collective properties resulting from parton fragmentation processes using high multiplicity jets in high-energy elementary collisions. Several novel observables are studied using the PYTHIA 8 Monte Carlo event generator. Experimental observation of such collectivity will offer a new view of non-perturbative QCD dynamics of multi-parton systems at the smallest scales. Absence of any collective effects may offer new insights into the role of quantum entanglement in the observed thermal behavior of particle production in high energy collisions.

    hep-phhep-exnucl-exnucl-thPRC(2023)·37 citations
11. 11*

    Validating the Earth's Core using Atmospheric Neutrinos with ICAL at INO

    Anil Kumar🇮🇳 · Sanjib Kumar Agarwalla🇮🇳

    The Iron Calorimeter (ICAL) detector at the proposed India-based Neutrino Observatory (INO) aims to detect atmospheric neutrinos and antineutrinos separately in the multi-GeV range of energies and over a wide range of baselines. By utilizing its charge identification capability, ICAL can efficiently distinguish ${\mu }^{-}$ and ${\mu }^{+}$ events. Atmospheric neutrinos passing long distances through Earth can be detected at ICAL with good resolution in energy and direction, which enables ICAL to see the density-dependent matter oscillations experienced by upward-going neutrinos in the multi-GeV range of energies. In this work, we explore the possibility of utilizing neutrino oscillations in the presence of matter to extract information about the internal structure of Earth complementary to seismic studies. Using good directional resolution, ICAL would be able to observe 331 ${\mu }^{-}$ and 146 ${\mu }^{+}$ core-passing events with 500 kt$\cdot$yr exposure. With this exposure, we show for the first time that the presence of Earth's core can be independently confirmed at ICAL with a median $\Delta {\chi }^2$ of 7.45 (4.83) assuming normal (inverted) mass ordering by ruling out the simple two-layered mantle-crust profile in theory while generating the prospective data with the PREM profile. We observe that in the absence of charge identification capability of ICAL, this sensitivity deteriorates significantly to 3.76 (1.59) for normal (inverted) mass ordering.

    hep-phhep-exphysics.ins-detJHEP(2021)·31 citations
12. 12*

    Massive sterile neutrinos in the early universe: From thermal decoupling to cosmological constraints

    Leonardo Mastrototaro🇮🇹 · Pasquale Dario Serpico🇫🇷 · Alessandro Mirizzi🇮🇹 · Ninetta Saviano🇮🇹

    We consider relatively heavy neutrinos ${\nu }_H$, mostly contributing to a sterile state ${\nu }_s$, with mass in the range 10 MeV $\lesssim m_s\lesssim m_{\pi }\sim 135$ MeV, which are thermally produced in the early universe in collisional processes involving active neutrinos, and freezing out after the QCD phase transition. If these neutrinos decay after the active neutrino decoupling, they generate extra neutrino radiation, but also contribute to entropy production. Thus, they alter the value of the effective number of neutrino species $N_{\mathrm{eff}}$ as for instance measured by the cosmic microwave background (CMB), as well as affect primordial nucleosynthesis (BBN), notably ${}^4$He production. We provide a detailed account of the solution of the relevant Boltzmann equations. We also identify the parameter space allowed by current Planck satellite data and forecast the parameter space probed by future Stage-4 ground-based CMB observations, expected to match or surpass BBN sensitivity.

    hep-phastro-ph.COPRD(2021)·32 citations
13. 13*

    Constraints on Tsallis Cosmology from Big Bang Nucleosynthesis and Dark Matter Freeze-out

    Anish Ghoshal🇮🇹 · Gaetano Lambiase🇮🇹

    We consider Tsallis cosmology as an approach to thermodynamic gravity and derive the bound on the Tsallis parameter to be $\beta <2$ by using the constraints derived from the formation of the primordial light elements, Helium, Deuterium and Litium, from the observational data from Big Bang Nucleosynthesis (BBN) which allows only a very tiny deviation from General Relativity (GR). Next we consider thermal dark matter (DM) freeze-out mechanism in Tsallis cosmological era and derive bounds on the Tsallis parameter from the observed DM relic abundance to be $1-\beta <10^{-5}$.

    ↳ astro-ph.COgr-qchep-ph35 citations
14. 14*

    Spectral-temporal features of repeating ( one-off ) FRBs and Axion Star

    Aiichi Iwazaki🇯🇵

    The fast radio bursts ( FRBs ) are energetic radio bursts with millisecond duration only observed at radio frequencies. The generation mechanism is still mysterious. We have proposed a generation mechanism of both repeating and one-off FRBs. They arise from the axion star collision with neutron star or magnetized accretion disk of galactic black hole. Once we accept the existence of the axions, we find that the mechanism well explain previously observed spectral-temporal features. In this paper we show that it also explains recently observed phenomena such as downward drifting in the repeating FRBs, etc.. Analysis of the downward drifting based on Doppler effects has been presented in recent papers, in which a superradiance system of molecular or atom has been proposed as a source of FRBs. We apply the analysis to our mechanism and find that it well explains the relation between the downward drifting rate and the duration of the repeating FRBs. The Doppler effects lead to the fact that the duration of radio burst with higher center frequency is shorter than that of radio burst with lower center frequency in the repeating FRBs. Our generation mechanism naturally explain polarization angle swing observed in the repeating FRB180301 and one-off FRBs. We also discuss the association between the FRB200428 and magnetar SGR J1935+2154. The X ray burst observed just after the observation of the FRB could be triggered by the axion star collision with the magnetar. We also explain the consistency of our generation mechanism with observed spectral-temporal differences in the repeating and one-off FRBs, e.g. longer duration ( smaller flux density ) of repeating FRBs than duration ( flux density ) of one-off FRBs.

    ↳ astro-ph.HEhep-phPRD(2021)·6 citations
15. 15*

    Intermittency analysis of proton numbers in heavy-ion collisions at energies available at the BNL Relativistic Heavy Ion Collider

    Jin Wu🇨🇳 · Yufu Lin🇨🇳 · Zhiming Li🇨🇳 · Xiaofeng Luo🇨🇳 · Yuanfang Wu🇨🇳

    Local density fluctuations near the QCD critical point has been suggested to exhibit a power-law behavior which can be probed by an intermittency analysis on scaled factorial moment (SFM) in relativistic heavy-ion collisions. The collision energy and centrality dependence of the second-order SFMs are systematically investigated in Au $+$ Au collisions at $\sqrt{s_{NN}}$ = 7.7, 11.5, 19.6, 27, 39, 62.4, and 200 GeV within the UrQMD model. We estimate the noncritical background in the measurement of intermittency and propose a cumulative variable method to effectively remove the background contributions. We further study the effect of particle detection efficiency by implementing the RHIC (STAR) experimental tracking efficiencies in the UrQMD events. A cell-by-cell method is proposed for experimental application of efficiency corrections on SFM. This work can provide a guidance of background subtraction and efficiency correction for the experimental measurement of intermittency in the search of the QCD critical point in heavy-ion collisions.

    ↳ nucl-thhep-phnucl-exPRC(2021)·20 citations
16. 16*

    Risking your NEC

    Carlos Hoyos🇪🇸 · Niko Jokela🇫🇮 · Jose Manuel Penín🇫🇮 · Alfonso V. Ramallo🇪🇸 · Javier Tarrío🇫🇮

    Energy conditions, especially the null energy condition (NEC), are generically imposed on solutions to retain a physically sensible classical field theory and they also play an important role in the AdS/CFT duality. Using this duality, we study non-trivially deformed strongly coupled quantum field theories at large-$N_c$. The corresponding dual classical gravity constructions entail the use of radially non-monotonic D-brane distributions. The gravity backgrounds are supersymmetric and hence perturbatively stable, and do not possess curvature singularities. There are no short-cuts through the bulk spacetime for signal propagation which assures that the field theory duals are causal. Nevertheless, some of our solutions violate the NEC in the gravity dual. In these cases the non-monotonicity of the D-brane distributions is reflected in the properties of the renormalization group flow: none of the $c$-functions proposed in the literature are monotonic. This further suggests that the non-monotonic behavior of the $c$-functions within previously known anisotropic backgrounds does not originate from the breaking of Lorentz invariance. We surmise that NEC violations induced by quantum corrections also need to be considered in holographic duals, but can be studied already at the classical level.

    ↳ hep-thgr-qchep-phJHEP(2021)·16 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.