Fri·May 26, 2023Friday·May 26, 2023

1. 01*

   Imperfect Axion Precludes the Domain Wall Problem

   Yue Zhang🇨🇦

   The QCD axion needs not be an exact pseudoscalar for solving the strong CP problem. Its imperfectness can play a profound role cosmologically. We propose effective operators, where the Peccei-Quinn field linearly couples to Standard Model particles, provide a dynamical solution to the domain wall problem that prevails in post-inflationary axion models with discrete symmetry. Such interactions generate a thermal potential that drives the axion field to a universal value throughout the universe at high temperatures thus preventing the birth of domain walls when the QCD potential switches on. We discuss generic conditions for this mechanism to work and several concrete examples. Combining with existing electric dipole moment and fifth force constraints, a lower bound on the axion mass is obtained around $10^{-5}$\,eV. Our findings make a strong case for complementary axion searches with both quality preserving and violating interactions.

   hep-phastro-ph.COPRL(2024)·13 citations
2. 02*

   Imprints of the nuclear symmetry energy slope in gravitational wave signals emanating from neutron stars

   Luiz L. Lopes🇧🇷 · Victor B. T. Alves🇧🇷 · César O. V. Flores🇧🇷 · German Lugones🇧🇷

   We investigate possible traces of the nuclear symmetry energy slope ($L$) in the gravitational wave emission of neutron stars. For fixed stellar mass values, we examine how the slope influences the stellar radius, compactness, the tidal deformability, the frequency of the quadrupole fundamental fluid mode, and the damping time of the mode due to the gravitational wave emission. We demonstrate that all these physical quantities are sensitive to the slope and could potentially impose significant constraints on it.

   hep-phgr-qcnucl-thPRD(2023)·13 citations
3. 03*

   $T-\mu$ quark matter phase transitions and critical end point in nonlocal PNJL models

   J.P. Carlomagno🇦🇷 · S.A. Ferraris🇦🇷 · D. Gómez Dumm🇦🇷 · A.G. Grunfeld🇦🇷

   We study the $T-\mu$ phase diagram of quark matter under the influence of a strong uniform magnetic field in the framework of a nonlocal extension of the Polyakov Nambu Jona Lasinio model (PNJL). The existence of a critical end point (CEP) is found for the whole considered range of the magnetic field (up to 1 $Ge{V}^2$). We analyze the location of this CEP as a function of the external field and discuss the presence of inverse magnetic catalysis for nonzero chemical potentials. Our results show that the temperature of the CEP decreases with the magnetic field, in contrast to the behavior observed in local NJL/PNJL models.

   hep-phPRD(2023)·7 citations
4. 04*

   Constraining the chameleon-photon coupling with atomic spectroscopy

   Benjamin Elder🇺🇸 · Jeremy Sakstein🇺🇸

   We compute bounds from atomic spectroscopy on chameleon fields that couple to the photon. Chameleons are a wide class of scalar field models that generically lead to screened fifth forces and a host of novel phenomenologies, particularly when the photon coupling is included. We account for perturbations to the atomic energy levels from both the scalar field "fifth force" and the scalar field's correction to the electric field. We also account for the electromagnetic interaction's contribution to the scalar charge of the proton, which enables a considerably wider class of models to be tested than without this effect. We find bounds that cover different areas of chameleon parameter space. Some regions are redundant with existing experiments, particularly $g-2$, confirming that those models are ruled out. Other regions were previously unconstrained, and a range of models spanning approximately four orders of magnitude in chameleon coupling parameters are excluded for the first time.

   hep-phgr-qcphysics.atom-phPRD(2024)·12 citations
5. 05*

   Regge trajectories for the doubly heavy diquarks

   Xia Feng🇨🇳 · Jiao-Kai Chen🇨🇳 · Jia-Qi Xie🇨🇳

   The concept of diquark is important for understanding hadron structure and high-energy particle reactions. We attempt to apply the Regge trajectory approach to the doubly heavy diquarks. We present a method for determining the parameters in the diquark Regge trajectory. The spectra of diquarks $(cc)$, $(bb)$, and $(bc)$ are obtained by using the {\rt} approach and are found to agree with other theoretical results. The diquark Regge trajectory becomes a new and very simple approach for estimating the spectra of diquarks.

   hep-phPRD(2023)·18 citations
6. 06*

   $Z_{cs}$, $Z_c$ and $Z_b$ states under the complex scaling method

   Jian-Bo Cheng🇨🇳 · Bo-Lin Huang🇨🇳 · Zi-Yang Lin🇨🇳 · Shi-Lin Zhu🇨🇳

   We investigate the $Z_b$, $Z_c$ and $Z_{cs}$ states within the chiral effective field theory framework and the $S$-wave single channel molecule picture. With the complex scaling method, we accurately solve the Schrödinger equation in momentum space. Our analysis reveals that the $Z_b(10610)$, $Z_b(10650)$, $Z_c(3900)$ and $Z_c(4020)$ states are the resonances composed of the $S-$wave $(B{\bar{B}}^{\ast }+B^{\ast }\bar{B})/\sqrt{2}$, $B^{\ast }{\bar{B}}^{\ast }$, $(D{\bar{D}}^{\ast }+D^{\ast }\bar{D})/\sqrt{2}$ and $D^{\ast }{\bar{D}}^{\ast }$, respectively. Furthermore, although the $Z_{cs}(3985)$ and $Z_{cs}(4000)$ states exhibit a significant difference in width, these two resonances may originate from the same channel, the $S-$wave $(D_s{\bar{D}}^{\ast }+D_s^{\ast }\bar{D})/\sqrt{2}$. Additionally, we find two resonances in the $S-$wave $D_s^{\ast }{\bar{D}}^{\ast }$ channel, corresponding to the $Z_{cs}(4123)$ and $Z_{cs}(4220)$ states that await experimental confirmation.

   hep-phhep-exhep-latnucl-thEPJC(2023)·10 citations
7. 07*

   The magnetic properties of a deuteron $r_m$ from the AdS/QCD hard-wall model

   Minaya Allahverdiyeva🇦🇿 · Narmin Huseynova🇦🇿 · Shahin Mamedov🇦🇿 · Jannat Samadov🇦🇿

   The deuteron is a spin1 particle and due to current conservation and the P and C invariance of the EM interaction, it has three EM form factors in the one photon exchange (OPE) approximation, which include the charge GC(Q2), quadrupole GQ(Q2) and magnetic GM(Q2) form factors and was calculated in [1, 2, 3] at a zero temperature within soft-wall and hard-wall models AdS/QCD. In this work, we numerically calculated the deuteron magnetic radius RM in the framework of the hard-wall model of AdS/QCD and compare our results with the experimental data and soft-wall model results [2]

   hep-phnucl-th0 citations
8. 08*

   Quantum version of transport coefficients in Nambu--Jona-Lasinio model at finite temperature and strong magnetic field

   Aritra Bandyopadhyay🇩🇪 · Snigdha Ghosh🇮🇳 · Ricardo L.S. Farias🇧🇷 · Sabyasachi Ghosh🇮🇳

   We have estimated parallel and perpendicular components of electrical conductivity and shear viscosity of quark matter at finite magnetic field and temperature by using their one-loop Kubo expressions in the framework of Nambu--Jona-Lasinio (NJL) model. At finite magnetic field, a non-trivial medium dependence of those quantities can be found. Previously these NJL-profiles have been addressed in relaxation time approximation, where cyclotron motion of quarks with medium dependent mass plays the key role. With respect to the earlier estimations, the present work provides further enriched profiles via Kubo framework, where field theoretical descriptions of quark transport with medium dependent mass and (Landau) quantized energy have been identified as the key ingredients. Hence the present study can be considered as the complete quantum field theoretical description of the transport coefficients in the framework of NJL model at finite temperature and magnetic field.

   hep-phEPJC(2023)·13 citations
9. 09*

   Predicting the Exclusive Diffractive Electron-Ion Cross Section at small $x$ with Machine Learning in Sar$t$re

   Jaswant Singh🇮🇳 · Tobias Toll🇮🇳

   The event generator Sar$t$re has been used extensively for simulations of electron-ion collisions in preparation for the Electron-Ion Collider (EIC). Sar$t$re simulates exclusive diffraction in $e$A collisions, in principle for any nuclear species and exclusive final state, usually a vector meson. The coherent and incoherent cross sections for each process are calculated in the colour dipole model for small $x$ from the first and second moments of the respective amplitude, averaged over initial state spatial configurations. Taking these averages is a very CPU demanding task. In order to function as an efficient event generator, these amplitude moments are saved into lookup tables which are used as input for the event generation, making the latter a very fast process. However, there are many recent and ongoing developments of the dipole models underlying the calculations, both in terms of fits of the model parameters to new data as well as new parametrisations of the dipole or proton geometries. Therefore, it is desirable to have a more flexible method for producing the lookup tables. Here, we propose a method using neural networks which can reduce the table production time by 90% while retaining the same precision in the resulting cross sections.

   hep-phComput.Phys.Commun.(2023)·3 citations
10. 10*

    Identifying physics beyond SMEFT in the angular distribution of ${\Lambda }_b\to {\Lambda }_c(\to \Lambda \pi )\tau {\bar{\nu }}_{\tau }$ decay

    Siddhartha Karmakar🇮🇳 · Susobhan Chattopadhyay🇮🇳 · Amol Dighe🇮🇳

    In the Standard Model Effective Field Theory (SMEFT), the $SU(2{)}_L\times U(1{)}_Y$ symmetry of the Standard Model is linearly realized. However, it is possible that more general effective field theories, such as the Higgs Effective Field Theory (HEFT) where this symmetry is realized non-linearly, are needed to describe the data. Identifying physics beyond SMEFT could shed light on the nature of Higgs and the realization of the electroweak symmetry. We explore the possibility of such an identification by studying the effects of scalar and vector new-physics operators on the angular distribution of ${\Lambda }_b\to {\Lambda }_c(\to \Lambda \pi )\tau {\bar{\nu }}_{\tau }$. This decay is sensitive to the 6-dimensional effective operator $O_V^{LR}\equiv (\bar{\tau }{\gamma }^{\mu }{P}_L{\nu }_{\tau })(\bar{c}{\gamma }_{\mu }{P}_{R}b)$, which is present in HEFT but suppressed in SMEFT. We identify the angular observables that can have significant contributions from $O_V^{LR}$, and hence would be useful for probing not only BSM physics but also physics beyond SMEFT. We further find that constraining the branching ratio of $B_c\to \tau {\bar{\nu }}_{\tau }$ would be crucial for performing this task.

    hep-phPRD(2024)·13 citations
11. 11*

    On practical naturalness and its implications for weak scale supersymmetry

    Howard Baer🇺🇸 · Vernon Barger🇺🇸 · Dakotah Martinez🇺🇸 · Shadman Salam🇧🇩

    We revisit the various measures of naturalness for models of weak scale supersymmetry including 1. electroweak (EW) naturalness, 2. naturalness via sensitivity to high scale parameters (EENZ/BG), 3. sensitivity of Higgs soft term due to high scale (HS) radiative corrections and 4. stringy naturalness (SN) from the landscape. The EW measure is most conservative and seems unavoidable; it is also model independent in that its value is fixed only by the weak scale spectra which ensues, no matter which model is used to generate it. The EENZ/BG measure is ambiguous depending on which ``parameters of ignorance'' one includes in the low energy effective field theory (LE-EFT). For models with calculable soft breaking terms, then the EENZ/BG measure reduces to the tree-level EW measure. The HS measure began life as a figurative expression and probably shouldn't be taken more seriously than that. SN is closely related to EW naturalness via the atomic principle, although it is also sensitive to the distribution of soft terms on the landscape. If the landscape favors large soft terms, as in a power law distribution, then it favors m(h) ~ 125 GeV along with sparticles beyond present LHC reach. In this context, SN appears as a probability measure where more natural models are expected to be more prevalent on the landscape than finetuned models. We evaluate by how much the different measures vary against one another with an eye to determining by how much they may overestimate finetuning; we find overestimates can range up to a factor of over 1000. In contrast to much of the literature, we expect the string landscape to favor EW natural SUSY models over finetuned models so that the landscape is not an alternative to naturalness.

    hep-phPRD(2023)·20 citations
12. 12*

    Dark Higgs Bosons at Colliders

    Torben Ferber🇩🇪 · Alexander Grohsjean🇩🇪 · Felix Kahlhoefer🇩🇪

    The Large Hadron Collider (LHC) has confirmed the Higgs mechanism to be responsible for generating mass in the Standard Model (SM), making it attractive to also consider spontaneous symmetry breaking as the origin of mass for new particles in a dark sector extension of the SM. Such a dark Higgs mechanism may in particular give mass to a dark matter candidate and to the gauge boson mediating its interactions (called dark photon). In this review we summarise the phenomenology of the resulting dark Higgs boson and discuss the corresponding search strategies with a focus on collider experiments. We consider both the case that the dark Higgs boson is heavier than the SM Higgs boson, in which case leading constraints come from direct searches for new Higgs bosons as well missing-energy searches at the LHC, and the case that the dark Higgs boson is (potentially much) lighter than the SM Higgs boson, such that the leading sensitivity comes from electron-positron colliders and fixed-target experiments. Of particular experimental interest for both cases is the associated production of a dark Higgs boson with a dark photon, which subsequently decays into SM fermions, dark matter particles or long-lived dark sector states. We also discuss the important role of exotic decays of the SM-like Higgs boson and complementary constraints arising from early-universe cosmology, astrophysics and direct searches for dark matter in laboratory experiments.

    hep-phhep-exPPNP(2024)·68 citations
13. 13*

    Thermodynamics and phase diagrams of the Polyakov quark-meson model with on-shell versus curvature mass parameter fixing

    Suraj Kumar Rai🇮🇳 · Vivek Kumar Tiwari🇮🇳

    The Quantum Chromodynamics (QCD) phase structure has been studied using the Polyakov-loop augmented quark-meson model (PQM) in the extended mean field approximation (e-MFA) where the quark one-loop vacuum term is included.~When the divergent vacuum term is regularized in the minimal subtraction scheme and the curvature meson masses are used to fix the parameters,~the Polyakov quark-meson model with the vacuum term (PQMVT) becomes inconsistent as the curvature masses are determined by calculating the self energies at zero momentum.~The above inconsistency is remedied by the on-shell parameter fixing when the pion decay constant and the pole masses of the mesons are put into the relation of the couplings and running mass parameter by using the on-shell and the minimal subtraction renormalization scheme.~Combining the modified chiral effective potential of the on-shell renormalized quark-meson model (RQM) with the Polyakov-loop potential that mimics the physics of the confinement-deconfinement transition,~we get the renormalized Polyakov quark-meson (RPQM) model.~The phase diagrams and the thermodynamics details for the PQM, PQMVT and RPQM model, have been computed and compared for different forms of the Polyakov-loop potentials with and without the quark back-reaction.~The results have also been compared with the available lattice QCD data.~The so called quarkyonic phase region in the phase diagram, where the chiral symmetry is restored but the quarks and anti-quarks are still confined,~gets reduced by the quark back-reaction in the unquenched Polyakov-loop potential.~It altogether disappears for the chemical potential dependent parameter $T_0\equiv T_0(\mu )$ in the Log or the PolyLog-glue form of the Polyakov-loop potential in the RPQM model.

    hep-phnucl-thPRD(2023)·8 citations
14. 14*

    Higgs Inflation via the Metastable Standard Model Potential, Generalised Renormalisation Frame Prescriptions and Predictions for Primordial Gravitational Waves

    J. McDonald🇬🇧

    Higgs Inflation via a metastable Standard Model Higgs Potential is possible if the effective Planck mass in the Jordan frame increases after inflation ends. Here we consider the predictions of this model independently of the dynamics responsible for the Planck mass transition. The classical predictions are the same as for conventional Higgs Inflation. The quantum corrections are dependent upon the conformal frame in which the effective potential is calculated. We generalise beyond the usual Prescription I and II renormalisation frame choices to include intermediate frames characterised by a parameter $\alpha$. We find that the model predicts a well-defined correlation between the values of the scalar spectral index $n_s$ and tensor-to-scalar ratio $r$. For values of $n_s$ varying between the 2-$\sigma$ Planck observational limits, we find that $r$ varies between 0.002 and 0.005 as $n_s$ increases, compared to the classical prediction of 0.003. Therefore significantly larger or smaller values of $r$ are possible, which are correlated with larger or smaller values of $n_s$. In addition, the model can be compatible with the larger values of $n_s$ predicted by Early Dark Energy solutions to the Hubble tension, with correspondingly larger values of $r$. The model can be tested via the detection of primordial gravitational waves by the next generation of CMB polarisation experiments.

    hep-phJCAP(2024)·2 citations
15. 15*

    Capability of the proposed long-baseline experiments to probe large extra dimension

    Samiran Roy🇮🇹

    Future long-baseline experiments will play an important role in exploring physics beyond the standard model. One such new physics concept is the large extra dimension (LED), which provides an elegant solution to the hierarchy problem. This model also explains the small neutrino mass in a natural way. The presence of LED modifies the standard neutrino oscillation probabilities. Hence, the long-baseline experiments are sensitive to the LED parameters. We explore the potential of the three future long-baseline neutrino experiments, namely T2HK, ESSnuSB, and DUNE, to probe the LED parameter space. We also compare the capability of the charged and neutral current measurements at DUNE to constrain the LED model. We find that T2HK will provide more stringent bounds on the largest compactification radius ($R_{\mathrm{ED}}$) compared to the DUNE and ESSnuSB experiments. At $90\%$ C.L., T2HK can exclude $R_{\mathrm{ED}}\sim 0.45(0.425)$ $\mu$m for the normal (inverted) mass hierarchy scenario.

    hep-phPRD(2023)·10 citations
16. 16*

    The complex heavy-quark potential with the Gribov-Zwanziger action

    Manas Debnath🇮🇳 · Ritesh Ghosh🇮🇳 · Najmul Haque🇮🇳

    Gribov-Zwanziger prescription in Yang-Mills theory improves the infrared dynamics. In this work, we study the static potential of a heavy quark-antiquark pair with the HTL resummed perturbation method within the Gribov-Zwanziger approach at finite temperature. The real and imaginary parts of the heavy quark complex potential are obtained from the one-loop effective static gluon propagator. The one-loop effective gluon propagator is obtained by calculating the one-loop gluon self-energies containing the quark, gluon, and ghost loop. The gluon and ghost loops are modified in the presence of the Gribov parameter. We also calculate the decay width from the imaginary part of the potential. We also discuss the medium effect of heavy quark potential with the localized action via auxiliary fields.

    hep-phnucl-thEPJC(2024)·19 citations
17. 17*

    Deconstructed Hypercharge: A Natural Model of Flavour

    Joe Davighi🇨🇭 · Ben A. Stefanek🇨🇭

    The flavour puzzle is one of the greatest mysteries in particle physics. A `flavour deconstruction' of the electroweak gauge symmetry, by promoting at least part of it to the product of a third family factor (under which the Higgs is charged) times a light family factor, allows one to address the flavour puzzle at a low scale due to accidentally realised $U(2{)}^5$ flavour symmetries. The unavoidable consequence is new heavy gauge bosons with direct couplings to the Higgs, threatening the stability of the electroweak scale. In this work, we propose a UV complete model of flavour based on deconstructing only hypercharge. We find that the model satisfies finite naturalness criteria, benefiting from the smallness of the hypercharge gauge coupling in controlling radiative Higgs mass corrections and passing phenomenological bounds. Our setup allows one to begin explaining flavour at the TeV scale, while dynamics solving the large hierarchy problem can lie at a higher scale up to around 10 TeV - without worsening the unavoidable little hierarchy problem. The low-energy phenomenology of the model is dominated by a single $Z^{\prime }$ gauge boson with chiral and flavour non-universal couplings, with mass as light as a few TeV thanks to the $U(2{)}^5$ symmetry. The natural parameter space of the model will be probed by the HL-LHC and unavoidably leads to large positive shifts in the $W$-boson mass, as well as an enhancement in $\text{Br}(B_{s,d}\to {\mu }^{+}{\mu }^{-})$. Finally, we show that a future electroweak precision machine such as FCC-ee easily has the reach to fully exclude the model.

    hep-phhep-exJHEP(2023)·59 citations
18. 18*

    Proposal to use LHC general-purpose detectors in "beam-dump" measurements for long-lived particles

    Bhaskar Dutta🇺🇸 · Doojin Kim🇺🇸 · Hyunyong Kim🇺🇸

    We propose a novel scheme for performing a beam-dump-like experiment with the general-purpose detectors (ATLAS and CMS) at the LHC. Collisions of high-energy protons result in jets containing a number of energetic hadrons and electromagnetic objects that are essentially "dumped" to hadronic and electromagnetic calorimeters, respectively, and induce the production of secondary hadrons, electrons, and photons in calorimetric showers. We envision a situation where new physics particles are produced by the interactions of these secondary particles inside the calorimeters. For proof of principles, we consider the axion-like particles (ALPs) produced via the Primakoff process in the presence of their interaction with photons at CMS. We argue that the drift tube chambers and the ME0 module of the muon system can serve as detectors to record the photons from the ALP decay, demonstrating that assuming the background level can be controlled as discussed in this work, the resulting sensitivity reach is competitive due to their close proximity to the signal source points. We further show that the LHC does not suffer from a barrier, dubbed beam-dump "ceiling", that typical beam-dump experiments hardly surpass. This gives the LHC great potential to explore a wide range of parameter space. This analysis can be extended to investigate various types of light mediators with couplings to the Standard Model leptons and quarks.

    hep-phhep-exPLB(2025)·9 citations
19. 19*

    Bremsstrahlung-induced Gravitational Waves in Monomial Potentials during Reheating

    Basabendu Barman🇵🇱 · Nicolás Bernal🇦🇪 · Yong Xu🇩🇪 · Óscar Zapata🇨🇴

    We discuss the production of primordial gravitational waves (GW) from radiative inflaton decay during the period of reheating, assuming perturbative decay of the inflaton either into a pair of bosons or fermions, leading to successful reheating satisfying constraint from Big Bang nucleosynthesis. Assuming that the inflaton $\varphi$ oscillates in a general monomial potential $V(\varphi )\propto {\varphi }^n$, which results in a time-dependent inflaton decay width, we show that the resulting stochastic GW background can have optimistic detection prospects, especially in detectors that search for a high-frequency GW spectrum, depending on the choice of $n$ that determines the shape of the potential during reheating. We also discuss how this GW energy density may affect the measurement of $\Delta N_{\text{eff}}$ for bosonic and fermionic reheating scenarios.

    hep-phastro-ph.COPRD(2023)·50 citations
20. 20*

    Power Counting to Saturation

    Iain Stewart🇺🇸 · Varun Vaidya🇺🇸

    We present a description of saturation in small $x$ deep inelastic scattering from power counting in a top-down effective theory derived from QCD. A factorization formula isolates the universal physics of the nucleus at leading power in $x$. The onset of saturation is then understood as a breakdown in the expansion in an emergent power counting parameter, which is defined by the matrix element of a gauge invariant operator. We identify a new radiation mode, which enables us to extend previous literature by distinguishing the appearance of the saturation scale from the transition to non-linear evolution.

    hep-phnucl-thPRD(2024)·11 citations
21. 21*

    Is the Aharonov-Bohm phase shift for a non-closed path a measurable quantity ?

    Masashi Wakamatsu🇯🇵

    There recently appear some interesting attempts to explain the AB-effect through the interaction between the charged particle and the solenoid current mediated by the exchange of a virtual photon. A vital assumption of this approach is that AB-phase shift is proportional to the change of the interaction energy between the charged particle and solenoid along the path of the moving charge. Accordingly, they insist that the AB-phase change along a path does not depend on the gauge choice so that the AB-phase shift for a non-closed path is in principle measurable. We however notice the existence of two fairly different discussions on the interaction energy between the solenoid and a charge particle, the one is due to Boyer and the other is due to Saldanha and others. In the present paper, based on a self-contained quantum mechanical treatment of the combined system of a solenoid, a charged particle, and the quantized electromagnetic fields, we show that both interaction energies of Boyer and of Saldanha are in fact gauge invariant at least for non-singular gauge transformations but they are destined to cancel each other. Our analysis rather shows that the origin of the AB-phase can be traced back to other part of our effective Hamiltonian. Furthermore, based on the path-integral formalism with our effective Lagrangian, we explicitly demonstrate that the AB-phase shift for a non-closed path is not a gauge-variant quantity, which means that it would not correspond to direct experimental observables.

    ↳ quant-phhep-phnucl-thEur.Phys.J.Plus(2024)·9 citations
22. 22*

    Non-thermal warm dark matter limits from small-scale structure

    Arka Banerjee🇮🇳 · Subinoy Das🇮🇳 · Anshuman Maharana🇮🇳 · Ethan O. Nadler🇺🇸 · Ravi Kumar Sharma🇮🇳

    We present small-scale structure constraints on sterile dark matter produced from a heavy mediator particle, inspired by models of moduli decay. Dark matter particles produced through this mechanism can contribute to the entire dark matter energy density but the particles have a non-thermal phase-space distribution; however, we show that the resulting linear matter power spectra can be mapped to effective thermal-relic warm dark matter models. This production mechanism is therefore subject to warm dark matter constraints from small-scale structure as probed by ultra-faint dwarf galaxy abundances and strong gravitational lensing flux ratio statistics. We use the correspondence to thermal-relic models to derive a lower bound on the non-thermal particle mass of $107\mathrm{keV}$, at $95\%$ confidence. These are the first and most stringent constraints derived on sterile dark matter produced via the heavy mediator decay scenario we consider.

    ↳ astro-ph.COhep-phhep-thPRD(2023)·6 citations
23. 23*

    Stringy Running Vacuum Model and current Tensions in Cosmology

    Adrià Gómez-Valent🇮🇹 · Nick E. Mavromatos🇬🇷 · Joan Solà Peracaula🇪🇸

    We discuss the potential alleviation of both the Hubble and the growth of galactic structure data tensions observed in the current epoch of Cosmology in the context of the so-called Stringy Running Vacuum Model (RVM) of Cosmology. This is a gravitational field theory coupled to matter, which, at early eras, contains gravitational (Chern-Simons (CS) type) anomalies and torsion, arising from the fundamental degrees of freedom of the massless gravitational multiplet of an underlying microscopic string theory. The model leads to RVM type inflation without external inflatons, arising from the quartic powers of the Hubble parameter that characterise the vacuum energy density due to primordial-gravitational-wave-induced anomaly CS condensates, and dominate the inflationary era. In modern eras, of relevance to this work, the gravitational anomalies are cancelled by chiral matter, generated at the end of the RVM inflationary era, but cosmic radiation and other matter fields are still responsible for a RVM energy density with terms exhibiting a quadratic-power-of-Hubble-parameter dependence, but also products of the latter with logarithmic $H$-dependencies, arising from potential quantum-gravity and quantum-matter loop effects. In this work, such terms are examined phenomenologically from the point of view of the potential alleviation of the aforementioned current tensions in Cosmology. Using standard information criteria, we find that these tensions can be substantially alleviated in a way consistent not only with the data, but also with the underlying microscopic theory predictions, associated with the primordial dynamical breaking of supergravity that characterise a pre-RVM-inflationary phase of the model.

    ↳ gr-qcastro-ph.COhep-phhep-thClass.Quant.Grav.(2024)·47 citations
24. 24*

    The electromagnetic fine-structure constant in primordial nucleosynthesis revisited

    Ulf-G. Meißner🇩🇪 · Bernard Ch. Metsch🇩🇪 · Helen Meyer🇩🇪

    We study the dependence of the primordial nuclear abundances as a function of the electromagnetic fine-structure constant $\alpha$, keeping all other fundamental constants fixed. We update the leading nuclear reaction rates, in particular the electromagnetic contribution to the neutron-proton mass difference pertinent to $\beta$-decays, and go beyond certain approximations made in the literature. In particular, we include the temperature-dependence of the leading nuclear reactions rates and assess the systematic uncertainties by using four different publicly available codes for Big Bang nucleosynthesis. Disregarding the unsolved so-called lithium-problem, we find that the current values for the observationally based ${}^2$H and ${}^4$He abundances restrict the fractional change in the fine-structure constant to less than $2\%$, which is a tighter bound than found in earlier works on the subject.

    ↳ hep-thastro-ph.COhep-phnucl-ex+1EPJA(2023)·23 citations
25. 25*

    Equation of state of nuclear matter and neutron stars: Quark mean-field model versus relativistic mean-field model

    Zhenyu Zhu🇨🇳 · Ang Li🇨🇳 · Jinniu Hu🇨🇳 · Hong Shen🇨🇳

    The equation of state of neutron-rich nuclear matter is of interest to both nuclear physics and astrophysics. We have demonstrated the consistency between laboratory and astrophysical nuclear matter in neutron stars by considering low-density nuclear physics constraints (from ${}^{208}$Pb neutron-skin thickness) and high-density astrophysical constraints (from neutron star global properties). We have used both quark-level and hadron-level models, taking the quark mean-field (QMF) model and the relativistic mean-field (RMF) model as examples, respectively. We have constrained the equation of states of neutron stars and some key nuclear matter parameters within the Bayesian statistical approach, using the first multi-messenger event GW170817/AT 2017gfo, as well as the mass-radius simultaneous measurements of PSR J0030+0451 and PSR J0740+6620 from NICER, and the neutron-skin thickness of ${}^{208}$Pb from both PREX-II measurement and ab initio calculations. Our results show that, compared with the RMF model, QMF model's direct coupling of quarks with mesons and gluons leads to the evolution of the in-medium nucleon mass with the quark mass correction. This feature enables QMF model a wider range of model applicability, as shown by a slow drop of the nucleon mass with density and a large value at saturation that is jointly constrained by nuclear physics and astronomy.

    ↳ nucl-thastro-ph.HEhep-phPRC(2023)·18 citations
26. 26*

    A Parametric Model for Self-Interacting Dark Matter Halos

    Daneng Yang🇺🇸 · Ethan O. Nadler🇺🇸 · Hai-Bo Yu🇺🇸 · Yi-Ming Zhong🇺🇸

    We propose a parametric model for studying self-interacting dark matter (SIDM) halos. The model uses an analytical density profile, calibrated using a controlled N-body SIDM simulation that covers the entire gravothermal evolution, including core-forming and -collapsing phases. By normalizing the calibrated density profile, we obtain a universal description for SIDM halos at any evolution phase. The model allows us to infer properties of SIDM halos based on their cold dark matter (CDM) counterparts. As a basic application, we only require two characteristic parameters of an isolated CDM halo at $z=0$. We then extend the model to incorporate effects induced by halo mass changes, such as major mergers or tidal stripping, making it applicable to both isolated halos and subhalos. The parametric model is tested and validated using cosmological zoom-in SIDM simulations available in the literature.

    ↳ astro-ph.COhep-phJCAP(2024)·52 citations
27. 27*

    A study of medium effects in elastic $\pi N$ and $\pi A$ scatterings

    Hyeon-dong Han🇰🇷

    The elastic $\pi N$ scattering is investigated for the $I=3/2$ channel dominated by the $\Delta (1232)$ resonance at finite baryon density, employing the effective Lagrangian approach at the tree-level Born approximation. The quark-meson coupling (QMC) model is employed to describe the in-medium baryon properties that are constructed at the quark level, such as the nucleon and $\Delta$ masses, and $\Delta$ full decay width. I reproduce the experimental data of the cross-section in a vacuum as a justification of our approach and then analyze the in-medium total and differential cross-sections as well as proton-spin asymmetry. Following the results of the in-medium elastic $\pi N$ scattering calculation, the elastic $\pi A$ scattering is investigated at finite baryon density in the framework of the Eikonal Glauber model for the light nuclei, ${}^4\mathrm{He}$ and ${}^{12}\mathrm{C}$. For the description of the finite nuclei, the Wood-Saxon density profile, and an expansion of the charge distribution as a sum of Gaussians are employed in this study. The nuclear density distribution ${\rho }_A$, effective baryon mass $m_B^{\ast }$, in-medium decay width ${\Gamma }_{\Delta }^{\ast }$, and in-medium coupling constants $f_{\pi NN}^{\ast }$ and $f_{\pi N\Delta }^{\ast }$ are analyzed as well as the total cross-section. The results show that the effective baryon mass and cross-sections in the medium decrease as density increases except for the $\Delta$ decay width, which increases as the density increases. The elastic $\pi A$ scattering at the tree-level Born approximation reproduces well the experimental data for ${}^4\mathrm{He}$ but overestimates for ${}^{12}\mathrm{C}$. Results for the in-medium $\Delta$ resonance and other findings in this work will be relevant for the relativistic heavy-ion collision experiments.

    ↳ nucl-thhep-phnucl-ex0 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.