Mon·Feb 28, 2022Monday·February 28, 2022

1. 01*

   New Limits on Leptophilic Axionlike Particles and Majorons from ArgoNeuT

   Enrico Bertuzzo🇧🇷 · Ana Luisa Foguel🇧🇷 · Gabriel M. Salla🇧🇷 · Renata Zukanovich Funchal🇧🇷

   Axionlike particles are among the most studied extensions of the standard model. In this Letter we study the bounds that the ArgoNeuT experiment can put on the parameter space of two specific scenarios: leptophilic axionlike particles and Majorons. We find that such bounds are currently the most constraining ones in the (0.2 - 1.7) GeV mass range.

   hep-phhep-exPRL(2023)·22 citations
2. 02*

   Electroweak Phase Transition in the $Z_3$-invariant NMSSM: Implications of LHC and Dark matter searches and prospects of detecting the gravitational waves

   Arindam Chatterjee🇮🇳 · AseshKrishna Datta🇮🇳 · Subhojit Roy🇮🇳

   We study in detail the viability and the patterns of a strong first-order electroweak phase transition as a prerequisite to electroweak baryogenesis in the framework of $Z_3$-invariant Next-to-Minimal Supersymmetric Standard Model (NMSSM), in the light of recent experimental results from the Higgs sector, dark matter (DM) searches and those from the searches of the lighter chargino and neutralinos at the Large Hadron Collider (LHC). For the latter, we undertake thorough recasts of the relevant, recent LHC analyses. With the help of a few benchmark scenarios, we demonstrate that while the LHC has started to eliminate regions of the parameter space with relatively small ${\mu }_{\mathrm{eff}}$, that favors the coveted strong first-order phase transition, rather steadily, there remains phenomenologically much involved and compatible regions of the same which are yet not sensitive to the current LHC analyses. It is further noted that such a region could also be compatible with all pertinent theoretical and experimental constraints. We then proceed to analyze the prospects of detecting the stochastic gravitational waves, which are expected to arise from such a phase transition, at various future/proposed experiments, within the mentioned theoretical framework and find them to be somewhat ambitious under the currently projected sensitivities of those experiments.

   hep-phJHEP(2022)·46 citations
3. 03*

   Pion Partonic Distributions in the Statistical Model from Pion-induced Drell-Yan and $J/\Psi$ Production Data

   Claude Bourrely🇫🇷 · Wen-Chen Chang🇹🇼 · Jen-Chieh Peng🇺🇸

   We present a new analysis to extract pion parton distribution functions (PDFs) within the framework of the statistical model. Starting from the statistical model first developed for the spin-1/2 nucleon, we extend this model to describe the spin-0 pion. Based on a combined fit to both the pion-induced Drell-Yan data and the pion-induced $J/\Psi$ production data, a new set of pion PDFs has been obtained. The inclusion of the $J/\Psi$ production data in the combined fit has provided additional constraints for better determining the gluon distribution in the pion. We also compare the pion PDFs obtained in the statistical model with other existing pion PDFs.

   hep-phPRD(2022)·25 citations
4. 04*

   Benchmarking LHC searches for light 2HDM+$\mathbf{a}$ pseudoscalars

   Spyros Argyropoulos🇩🇪 · Ulrich Haisch🇩🇪

   Using two suitable benchmark scenarios that satisfy the experimental constraints on the total decay width of the $125\mathrm{GeV}$ Higgs boson, we determine the bounds on light CP-odd spin-0 states in the 2HDM+$a$ model that arise from existing LHC searches. Our work represents the first thorough study that considers the parameter space with $m_a\lesssim 100\mathrm{GeV}$ and should prove useful for 2HDM+$a$ interpretations of future ATLAS, CMS and LHCb searches for pseudoscalars with masses below the electroweak scale.

   hep-phhep-exSciPost Phys.(2022)·22 citations
5. 05*

   Crossing two-component dark matter models and implications for 511 keV $\gamma$-ray and XENON1T excesses

   P. Ko🇰🇷 · Chih-Ting Lu🇰🇷 · Ui Min🇰🇷

   We study scalar and fermionic crossing two-component dark matter (C2CDM) models with $U(1{)}_X$ dark gauge symmetry. This $U(1{)}_X$ gauge symmetry is broken via the dark Higgs mechanism of a dark Higgs field $\Phi$ and the dark photon becomes massive. On the other hand, the same dark Higgs field $\Phi$ also serves as a bridge between each component of two DM sectors such that the dark flavor-changing neutral current (DFCNC) interaction between them is induced. Moreover, the mass splitting between these two DM sectors is generated after $U(1{)}_X$ gauge symmetry breaking by nonzero $⟨\Phi ⟩$. We discuss the stability of DM candidates and allowed parameter space from the relic density and other constraints in C2CDM models. Some novel signatures with displaced vertices at Belle II are studied. Finally, the possible explanations of 511 keV $\gamma$-ray line and XENON1T excess in C2CDM models are discussed.

   hep-phhep-ex6 citations
6. 06*

   ${\mathbf{N}}_{\mathbf{eff}}$ from Excited DM state

   Wei Chao🇨🇳 · Jing-Jing Feng🇨🇳 · Ming-Jie Jin🇨🇳

   For a cold dark matter (DM) originating from the co-annihilation processes, there will be excited state(s) in the dark sector, that may decay or annihilate away shortly after their freeze-out. In this paper we investigate the impact of the decay of these excited states on the effective number of neutrino species, $N_{\mathrm{eff}}^{}$, which is an important cosmological parameter and will be tested by the future CMB-S4 project. We work in the framework of pseudo-Dirac DM mode via the Higgs portal. The relic density and the direct detection signal of the DM are calculated, which gives the available parameter space. Impacts of the excited state (the heavy component of the pseudo-Dirac fermion) on the decoupling of active neutrinos are investigated by solving Boltzmann equations of photon and neutrinos with collision term induced by the decay of the excited state. The numerical result shows that $|N_{\mathrm{eff}}^{}|$ can be of the order $10^{-4}$, which depends on the mass and lifetime of excited DM state.

   hep-phPRD(2023)·3 citations
7. 07*

   Sensitivity limits on the weak dipole moments of the top-quark at the Bestest Little Higgs Model

   E. Cruz-Albaro (1)🇲🇽 · A. Gutiérrez-Rodríguez (1) ((1) Zacatecas U.)🇲🇽

   We presented new researches for the sensitivity limits on the weak dipole moments of the top quark-$Z$ boson interactions in the context of the Bestest Little Higgs Model (BLHM). For this purpose, we derive the corresponding Feynman rules. Among the new contributions, there are those arising from the vertices of scalar bosons, vector bosons and heavy quarks contribution: $t{q}_i{S}_i$, ($S_i=h_0,H_0,A_0,{\varphi }^0,{\eta }^0,\sigma ,H^{\pm },{\varphi }^{\pm },{\eta }^{\pm }$); $t{q}_i{V}_i$, ($V_i=\gamma ,Z,W,Z^{\prime },W^{\prime }$); and $Z{q}_i{\bar{q}}_i$ ($q_i=b,t,B,T,T_5,T_6,T^{2/3},T^{5/3}$). With these new vertices, we calculate the one-loop contributions to the weak dipole moments $a_t^W$ and $d_t^W$ of the top-quark in several scenarios. We found that with the parameters of the BLHM of $m_{A_0}=1000$ GeV, $m_{{\eta }^0}=100$ GeV, $F=4000$ GeV, $f=[1000,3000]$ GeV and $\tan \beta =3$, the $a_t^W$ reaches values with a sensitivity of $a_t^W=2.49\times 10^{-4}-1.26\times 10^{-5}i$, $1.26\times 10^{-4}-5.41\times 10^{-6}i$, where the main contribution comes from the scalars $h_0$ and $H_0$, which couples to the top-quark of the Standard Model and the top-quarks of the BLHM. These values seem to be out of the reach of the expected experimental sensitivity of present experiments. However, experiments on future colliders are expected to be sensitive enough to measure the AWMDM of the top-quark. Our study complements other studies at the level of one-loop with an extended scalar sector.

   hep-phEur.Phys.J.Plus(2022)·11 citations
8. 08*

   Electroweak phase transition in the nearly aligned Higgs effective field theory

   Shinya Kanemura🇯🇵 · Ryo Nagai🇯🇵 · Masanori Tanaka🇯🇵

   We investigate the strongly first-order electroweak phase transition using an effective field theoretical approach. The standard effective field theory with finite number truncation of higher dimensional operators fails in the typical parameter space where the strongly first-order phase transition is realized because it cannot describe the non-decoupling quantum effect of new physics beyond the standard model. To parameterize the non-decoupling quantum effect, we employ the nearly aligned Higgs effective theory in which the Higgs potential is parameterized by a Coleman-Weinberg like form. Extending this framework with finite temperature corrections, we study the parameter space for realizing the strongly first-order phase transition, and estimate the gravitational wave produced at the phase transition.

   hep-phJHEP(2022)·27 citations
9. 09*

   Jet modifications from colour rope formation in dense systems of non-parallel strings

   Christian Bierlich🇸🇪 · Smita Chakraborty🇸🇪 · Gösta Gustafson🇸🇪 · Leif Lönnblad🇸🇪

   We revisit our rope model for string fragmentation that has been shown to give a reasonable description of strangeness and baryon enhancement in high-multiplicity pp events at the LHC. A key feature of the model is that the enhancement is driven by the increased string tension due to strings overlapping in dense systems. By introducing an improved space-time picture for the overlap between fragmenting strings, where also non-parallel strings are properly taken into account, we are now able to investigate the enhancement both in jets and in the underlying event in a consistent way.

   hep-phhep-thSciPost Phys.(2022)·14 citations
10. 10*

    Simulating Glueball Production in $N_f=0$ QCD

    David Curtin🇨🇦 · Caleb Gemmell🇨🇦 · Christopher B. Verhaaren🇺🇸

    In an $SU(N_c)$ gauge theory with zero light quark flavours $N_f=0$, the only hadronic states that form below the confinement scale are composite gluon states called glueballs. These minimal confining sectors arise in many Hidden Valley extensions of the Standard Model, including scenarios that could hold the solution to the dark matter question and the hierarchy problem. Quantitative study of dark glueball phenomenology requires an understanding of pure glue hadronization, which to date is severely lacking. In this work we show that significant progress can be made by combining a perturbative pure glue parton shower with a self-consistent and physically motivated parameterization of the unknown non-perturbative physics, thanks to the modest hierarchy between the glueball mass and the confinement scale. We make our simulation code available as the public GlueShower package, the first glueball generator for Hidden Valley theories, and perform preliminary studies of several glueball production observables, with theoretical uncertainties that take the full range of possible hadronization scenarios into account. We hope this will enable new studies of dark sector phenomenology that were previously inaccessible.

    hep-phhep-exPRD(2022)·27 citations
11. 11*

    Towards excluding a light $Z^{\prime }$ explanation of $b\to s{\ell }^{+}{\ell }^{-}$

    Andreas Crivellin🇨🇭 · Claudio Andrea Manzari🇨🇭 · Wolfgang Altmannshofer🇺🇸 · Gianluca Inguglia🇦🇹 · Paul Feichtinger🇦🇹 · Jorge Martin Camalich🇪🇸

    The discrepancies between $b\to s{\ell }^{+}{\ell }^{-}$ data and the corresponding Standard Model predictions constitute the most significant hints for new physics (at the TeV scale or below) currently available. In fact, many scenarios that can account for these anomalies have been proposed in the literature. However, only a single light new physics explanation, i.e. with a mass below the $B$ meson scale, is possible: a light $Z^{\prime }$ boson. In this article, we point out that improved limits on $B\to K^{(\ast )}\nu \nu$, including the experimental sensitivities required for a proper treatment of the necessarily sizable $Z^{\prime }$ width, together with the forthcoming Belle~II analyses of $e^{+}{e}^{-}\to {\mu }^{+}{\mu }^{-}+\mathrm{invisible}$, can rule out a $Z^{\prime }$ explanation of $b\to s{\ell }^{+}{\ell }^{-}$ data with a mass below $\approx 4$GeV. Importantly, such a light $Z^{\prime }$ is the only viable single particle solution to the $b\to s{\ell }^{+}{\ell }^{-}$ anomalies predicting $R(K^{(\ast )})>0$ in high $q^2$ bins, therefore providing an essential consistency test of data.

    hep-phhep-exPRD(2022)·26 citations
12. 12*

    Ultraviolet Freeze-in with a Time-dependent Inflaton Decay

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

    It is typically assumed that during reheating the inflaton decays with a constant decay width. However, this is not guaranteed and can have a strong impact on the dark matter (DM) genesis. In the context of the ultraviolet (UV) freeze-in mechanism, if the operators connecting the dark and visible sectors are of sufficiently high mass dimension, the bulk of the DM abundance is produced during and not after reheating. We study here the impact of a time-dependent decay width of the inflaton on the DM abundance, emphasizing the differences with respect to the cases where the decay is either instantaneous or constant. We also provide concrete examples for DM production via UV freeze-in, e.g., from 2-to-2 scatterings of standard model particles, or from inflaton scatterings or decays, elucidating how the time-dependence influences the DM yield.

    hep-phJCAP(2022)·56 citations
13. 13*

    Origin of Neutrino Masses on the Convex Cone of Positivity Bounds

    Xu Li🇨🇳 · Shun Zhou🇨🇳

    We exhibit the geometric structure of the convex cone in the linear space of the Wilson coefficients for the dimension-8 operators involving the left-handed lepton doublet $L$ and the Higgs doublet $H$ in the Standard Model effective field theory (SMEFT). The boundary of the convex cone gives rise to the positivity bounds on the Wilson coefficients, while the extremal ray corresponds to the unique particle state in the theory of ultra-violet completion. Among three types of canonical seesaw models for neutrino masses, we discover that only right-handed neutrinos in the type-I seesaw model show up as one of extremal rays, whereas the heavy particles in the type-II and type-III seesaw models live inside the cone. The experimental determination of the relevant Wilson coefficients close to the extremal ray of type-I seesaw model will unambiguously pin down or rule out the latter as the origin of neutrino masses. This discovery offers a novel way to distinguish the most popular seesaw model from others, and also strengthens the SMEFT as an especially powerful tool to probe new physics beyond the Standard Model.

    hep-phhep-exPRD(2023)·24 citations
14. 14*

    Basic Elements for Simulations of Standard Model Physics with Quantum Annealers: Multigrid and Clock States

    Marc Illa🇺🇸 · Martin J. Savage🇺🇸

    We explore the potential of D-Wave's quantum annealers for computing some of the basic components required for quantum simulations of Standard Model physics. By implementing a basic multigrid (including "zooming") and specializing Feynman-clock algorithms, D-Wave's Advantage is used to study harmonic and anharmonic oscillators relevant for lattice scalar field theories and effective field theories, the time evolution of a single plaquette of SU(3) Yang-Mills lattice gauge field theory, and the dynamics of flavor entanglement in four neutrino systems.

    ↳ quant-phhep-lathep-phnucl-thPRA(2022)·73 citations
15. 15*

    Symmetric Mass Generation in the 1+1 Dimensional Chiral Fermion 3-4-5-0 Model

    Meng Zeng🇺🇸 · Zheng Zhu🇨🇳 · Juven Wang🇺🇸 · Yi-Zhuang You🇺🇸

    Lattice regularization of chiral fermions has been a long-standing problem in physics. In this work, we present the density matrix renormalization group (DMRG) simulation of the 3-4-5-0 model of (1+1)D chiral fermions with an anomaly-free chiral U(1) symmetry, which contains two left-moving and two right-moving fermions carrying U(1) charges 3,4 and 5,0, respectively. Following the Wang-Wen chiral fermion model, we realize the chiral fermions and their mirror partners on the opposite boundaries of a thin strip of (2+1)D lattice model of multi-layer Chern insulator, whose finite-width implies the quantum system is effectively (1+1)D. By introducing carefully designed two sets of six-fermion local interactions to the mirror sector only, we demonstrate that the mirror fermions can be gapped out by the interaction beyond a critical strength without breaking the chiral U(1) symmetry, via the symmetric mass generation (SMG) mechanism. We show that the interaction-driven gapping transition is in the Berezinskii-Kosterlitz-Thouless (BKT) universality class. We determine the evolution of Luttinger parameters before the transition, which confirms that the transition happens exactly at the point when the interaction term becomes marginal. As the mirror sector is gapped after the transition, we check that the fermions in the light chiral fermion sector remain gapless, which provides the desired lattice regularization of chiral fermions.

    ↳ cond-mat.str-elhep-lathep-phhep-th+1PRL(2022)·73 citations
16. 16*

    History of Solar Neutrino Observations

    Masayuki Nakahata🇯🇵

    The first solar neutrino experiment led by Raymond Davis Jr. showed a deficit of neutrinos relative to the solar model prediction, referred to as the "solar neutrino problem" since the 1970s. The Kamiokande experiment led by Masatoshi Koshiba successfully observed solar neutrinos, as first reported in 1989. The observed flux of solar neutrinos was almost half the prediction and confirmed the solar neutrino problem. This problem was not resolved for some time due to possible uncertainties in the solar model. In 2001, it was discovered that the solar neutrino problem is due to neutrino oscillations by comparing the Super-Kamiokande and Sudbury Neutrino Observatory results, which was the first model-independent comparison. Detailed studies of solar neutrino oscillations have since been performed, and the results of solar neutrino experiments are consistent with solar model predictions when the effect of neutrino oscillations are taken into account. In this article, the history of solar neutrino observations is reviewed with the contributions of Kamiokande and Super-Kamiokande detailed.

    ↳ hep-exastro-ph.HEastro-ph.SRhep-ph+1PTEP(2022)·16 citations
17. 17*

    A Straight Lightning Bolt?! Observation of a Predicted Macro Dark Matter Signature

    Nathaniel Starkman🇨🇦 · Glenn D. Starkman🇺🇸 · Harrison Winch🇨🇦 · Jagjit Singh Sidhu🇨🇦

    Recently, four remarkably straight very brief flashes of light were captured on video in Perth, Australia within 0.5s of one another. Straight lightning was recently identified as a prediction of macroscopic dark matter (macros) -- a broad class of alternative candidates to particle dark matter. A sufficiently large macro passing through the atmosphere producing a straight column ofplasma would produce fluorescence, or, under atmospheric conditions conducive to lightning, seeda very straight lightning strike visible to the naked eye. Other explanations are considered, but areproblematic.

    ↳ astro-ph.GAastro-ph.COhep-ph1 citation
18. 18*

    Astrophysical Plasma Instabilities induced by Long-Range Interacting Dark Matter

    Akaxia Cruz🇺🇸 · Matthew McQuinn🇺🇸

    If dark matter (DM) is millicharged or darkly charged, collective plasma processes may dominate momentum exchange over direct particle collisions. Plasma streaming instabilities can couple the momentum of the DM to counter-streaming baryons or other DM and result in the counter-streaming fluids coming to rest with each other, just as happens for baryonic collisionless shocks in astrophysical systems. While electrostatic plasma instabilities are highly suppressed by Landau damping when DM is millicharged, in the cosmological situations of interest, electromagnetic instabilities such as the Weibel can couple momenta, assuming that the linear instability saturates in the manner typically found for baryonic plasmas. We find that the streaming of DM in the pre-Recombination universe is affected more strongly by direct collisions than collective processes, validating previous constraints. However, when considering magnetized Weibel and Firehose instabilities, the properties of the Bullet Cluster merger are likely to be substantially altered if $[q_{\chi }/m_{\chi }]\gtrsim 10^{-12}-10^{-11}$, where $[q_{\chi }/m_{\chi }]$ is the charge-to-mass ratio of the DM relative to that of the proton. The Weibel growth rates are even faster in the case of a dark-$U(1)$ charge, potentially ruling out $[q_{\chi }/m_{\chi }]\gtrsim 10^{-14}$ in the Bullet Cluster system, in agreement with previous work. The strongest previous limits on millicharged DM (mDM) arise from considering the spin-down of galactic disks. We show that plasma instabilities or tangled background magnetic fields could lead to diffusive propagation of the DM, weakening these spin-down limits. Thus, plasma instabilities may place some of the most stringent constraints over much of the millicharged, and our results corroborate previous extremely stringent potential constraints on the dark-charged parameter space.

    ↳ astro-ph.COastro-ph.GAhep-phJCAP(2023)·17 citations
19. 19*

    Friedel formula and Krein's theorem in complex potential scattering theory

    Peng Guo🇺🇸 · Vladimir Gasparian🇺🇸

    In this work, the generalization of Friedel formula and Krein's theorem in complex potential scattering theory is presented. The consequence of various symmetry constraints on dynamical system are discussed. In addition, Muskhelishvili-Omnès representation of Krein's theorem is also given and discussed.

    ↳ cond-mat.otherhep-phnucl-thPRResearch(2022)·14 citations
20. 20*

    Combined significance of spatial coincidence of high energy neutrinos from PSR B1509-58 by Super-Kamiokande and MACRO

    Shantanu Desai🇮🇳

    In their searches for astrophysical point sources of high energy neutrinos, both the Super-Kamiokande and MACRO neutrino detectors saw the largest angular excess from the same source, viz. PSR B1509-58. We estimate the probability for the observed number of events by {\it both} Super-Kamiokande and MACRO to be a chance coincidence due to atmospheric neutrino background. We find that this probability is about 0.4%, corresponding to 2.6$\sigma$ significance. We also propose some additional tests to ascertain if this excess corresponds to an astrophysical signal or is only a background event.

    ↳ astro-ph.HEhep-phJCAP(2022)·5 citations
21. 21*

    Nuclear force with LapH smearing

    Takuya Sugiura🇯🇵 · Yutaro Akahoshi🇯🇵 · Tatsumi Aoyama🇯🇵 · Takahiro M. Doi🇯🇵 · Takumi Doi🇯🇵

    The nuclear forces are determined by combining the HAL QCD method and a new type of source smearing technique. The new smearing is a projection to a space spanned by the lowest-lying eigenvectors of the free Laplacian operator on a lattice, which enables efficient calculation of hadron correlators at an affordable cost by utilizing the hadron-level momentum conservations. We find that this new approach reduces the statistical and systematic errors in the resultant nuclear forces.

    ↳ hep-lathep-phnucl-thPoS(2022)·2 citations
22. 22*

    Spatially-Resolved Band Gap and Dielectric Function in 2D Materials from Electron Energy Loss Spectroscopy

    Abel Brokkelkamp · Jaco ter Hoeve🇳🇱 · Isabel Postmes · Sabrya E. van Heijst🇳🇱 · Louis Maduro🇳🇱 · Albert V. Davydov · Sergiy Krylyuk · Juan Rojo🇳🇱 · Sonia Conesa-Boj🇳🇱

    The electronic properties of two-dimensional (2D) materials depend sensitively on the underlying atomic arrangement down to the monolayer level. Here we present a novel strategy for the determination of the band gap and complex dielectric function in 2D materials achieving a spatial resolution down to a few nanometers. This approach is based on machine learning techniques developed in particle physics and makes possible the automated processing and interpretation of spectral images from electron energy-loss spectroscopy (EELS). Individual spectra are classified as a function of the thickness with $K$-means clustering and then used to train a deep-learning model of the zero-loss peak background. As a proof-of-concept we assess the band gap and dielectric function of InSe flakes and polytypic WS${}_2$ nanoflowers, and correlate these electrical properties with the local thickness. Our flexible approach is generalizable to other nanostructured materials and to higher-dimensional spectroscopies, and is made available as a new release of the open-source EELSfitter framework.

    ↳ cond-mat.mtrl-scihep-phJ.Phys.Chem.A(2022)·3 citations
23. 23*

    Canonical and phenomenological formulations of spin hydrodynamics

    Asaad Daher🇵🇱 · Arpan Das🇵🇱 · Wojciech Florkowski🇵🇱 · Radoslaw Ryblewski🇵🇱

    Two formulations of relativistic hydrodynamics of particles with spin 1/2 are compared. The first approach, dubbed the canonical one, uses expressions for the energy-momentum and spin tensors that have properties that follow a direct application of Noether's theorem, which yields a totally antisymmetric spin tensor. The other one is based on a simplified form of the spin tensor and is commonly used in the current literature under the name of a phenomenological approach. We show that these two frameworks are equivalent, i.e., they can be directly connected by a suitably defined pseudogauge transformation, only if the first framework is initially improved by a suitable modification of the energy-momentum tensor (addition of a divergence-free term that cannot be interpreted as a pseudogauge). Our analysis uses arguments related to the positivity of entropy production. The latter turns out to be equivalent for the improved canonical and phenomenological frameworks.

    ↳ nucl-thhep-phPRC(2023)·65 citations
24. 24*

    Lorentz invariance violation (LIV) in some basic phenomena in quantum physics

    Z. Shafeei🇮🇷 · S. A. Alavi🇮🇷

    Lorentz symmetry is one of the cornerstone of both general relativity and the standard model of particle physics. We study the violation of Lorentz symmetry in some basic phenomena in atomic physics. Using the Green's function, and the source 4-current, the differential equation of 4-vector of electromagnetic potential is solved and the modified coulomb potential is obtained by some researchers. Using modified Coulomb potential, we find the corrections due to LIV on the spectrum of Hydrogen and Helium atoms. We also investigate the consequences of LIV on Stark, Zeeman and Spin orbit effects and obtain some upper bounds for the LIV coefficients.

    ↳ quant-phhep-phhep-thPoS(2022)·0 citations
25. 25*

    Orbits and adiabatic contraction in scalar field dark matter halos: revisiting the cusp-core problem in dwarf galaxies

    Kevin Pils🇦🇹 · Tanja Rindler-Daller🇦🇹

    Bose-Einstein-condensed dark matter, also called scalar-field dark matter (SFDM), has become a popular alternative to cold dark matter (CDM), because it predicts galactic cores, in contrast to the cusps of CDM halos ("cusp-core problem"). We continue the study of SFDM with a strong, repulsive self-interaction; the Thomas-Fermi regime of SFDM (SFDM-TF). In this model, structure formation is suppressed below a scale related to the TF radius $R_{\text{TF}}$, which is close to the radius of central cores in these halos. We investigate for the first time the impact of baryons onto realistic galactic SFDM-TF halo profiles by studying the process of adiabatic contraction (AC) in such halos. In doing so, we first analyse the underlying quantum Hamilton-Jacobi framework appropriate for SFDM and calculate dark matter orbits, in order to verify the validity of the assumptions usually required for AC. Then, we calculate the impact of AC onto SFDM-TF halos of mass $\sim 10^{11}{M}_{\odot }$, with various baryon fractions and core radii, $R_{\text{TF}}\sim (0.1-4)$ kpc, and compare our results with observational velocity data of dwarf galaxies. We find that AC-modified SFDM-TF halos with kpc-size core radii reproduce the data well, suggesting stellar feedback may not be required. On the other hand, halos with sub-kpc core radii face the same issue than CDM, in that they are not in accordance with galaxy data in the central halo parts.

    ↳ astro-ph.GAastro-ph.COhep-phMNRAS(2022)·3 citations
26. 26*

    Hadronization and Color Transparency

    Kai gallmeister🇩🇪 · Ulrich Mosel🇩🇪

    In this article we review our work on the production of hadrons in the nuclear environment. We work with a string-breaking model for the initial production of hadrons and with a quantum-kinetic transport model (GiBUU) to describe the final state interactions of the newly formed (pre)hadrons. The latter are determined both by the formation times and by the time-development of the hadron-hadron cross section. We first show that only a linear time-dependence is able to describe the available hadronization data. We then compare with detailed data from HERMES and JLAB; very good agreement is reached in all reactions studied without any tuning of parameters. We also repeat predictions of spectra for pions and kaons at JLAB@12GeV. We finally explain the absence of CT effects in the recent experiment on proton transparencies in quasielastic (QE) events on nuclei. We propose to look instead for CT effects on protons in semi-inclusive DIS (SIDIS) events.

    ↳ nucl-thhep-exhep-phnucl-exMDPI Physics(2022)·5 citations
27. 27*

    Neutron stars and phase diagram in a hard-wall AdS/QCD model

    Lorenzo Bartolini🇨🇳 · Sven Bjarke Gudnason🇨🇳 · Josef Leutgeb🇦🇹 · Anton Rebhan🇦🇹

    We study the phase diagram of (large-$N_c$) QCD using a simplistic holographic hard-wall model with a dynamical scalar field and a homogeneous Ansatz representing a smeared instanton/baryon density. The resulting phase diagram is qualitatively consistent with expectations, including a mesonic, baryonic, quarkyonic, and quark-gluon plasma phase. As in other holographic models, we also find a baryonic popcorn transition, which appears at large chemical potential as a crossover. We then evaluate the nuclear matter equation of state, which turns out to be rather stiff with a large peaked sound velocity above the conformal limit, construct corresponding neutron stars using the TOV equations, and finally use a full numerical gravity/hydrodynamics computation to extract the gravitational wave signal of neutron star mergers.

    ↳ hep-thastro-ph.HEhep-phnucl-thPRD(2022)·32 citations
28. 28*

    Casimir effect and Lorentz invariance violation

    S. A. Alavi🇮🇷

    The Casimir effect is one of the most direct manifestations of the existence of the vacuum quantum fluctuations, discovered by H. B Casimir in 1948. On the other hand, Lorentz invariance is one of the main and basic concepts in special relativity, which states that, the laws of physics are invariant under Lorentz transformation. In this work, we calculate the corrections imposed by LIV on Casimir effect (force). This may provide a direct probe to test LIV in nature.

    ↳ quant-phhep-phhep-thPoS(2022)·0 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.