Tue·Oct 15, 2019Tuesday·October 15, 2019

1. 01*

   Dark matter astrometry at underground detectors with multiscatter events

   Joseph Bramante🇨🇦 · Jason Kumar🇺🇸 · Nirmal Raj🇨🇦

   We show that current and imminent underground detectors are capable of precision astrometry of dark matter. First we show that galactic dark matter velocity distributions can be obtained from reconstructed tracks of dark matter scattering on multiple nuclei during transit; using the liquid scintillator neutrino detector SNO+ as an example, we find that the dark matter velocity vector can be reconstructed event-by-event with such a small uncertainty, that the precision of dark matter astrometry will be limited mainly by statistics. We then determine the number of dark matter events required to determine the dispersion speed, escape speed, and velocity anisotropies of the local dark matter halo, and also find that with as few as $\mathcal{O}(10)$ events, dark matter signals may be discriminated from potential backgrounds arising as power-law distributions. Finally, we discuss the prospects of dark matter astrometry at other liquid scintillator detectors, dark matter experiments, and the recently proposed MATHUSLA detector.

   hep-phastro-ph.HEhep-exPRD(2019)·39 citations
2. 02*

   New Insight about the Effective Restoration of U_A(1) Symmetry

   Xiang Li🇨🇳 · Wei-jie Fu🇨🇳 · Yu-xin Liu🇨🇳

   The effective restoration of the U_{A}(1) symmetry is revisited by implementing the functional renormalization group approach combining with the 2+1 flavor Polyakov-loop quark-meson model. A temperature-dependent 't Hooft term is taken to imitate the restoration of the U_{A}(1) symmetry. Order parameters, meson spectrum and mixing angles, especially the pressure and the entropy density of the system are calculated to explore the effects of different U_{A}(1) symmetry restoration patterns. We show then that the temperature for the restoration of the U_{A}(1) symmetry is much higher than that for the chiral symmetry SU_{A}(3).

   hep-phnucl-thPRD(2020)·10 citations
3. 03*

   Covariant calculation of a two-loop test of nonrelativistic QCD factorization

   Geoffrey T. Bodwin🇺🇸 · Hee Sok Chung🇩🇪 · June-Haak Ee🇰🇷 · U-Rae Kim🇰🇷 · Jungil Lee🇰🇷

   We test the nonrelativistic QCD factorization conjecture for inclusive quarkonium production at two loops by carrying out a covariant calculation of the nonrelativistic quantum chromodynamics (NRQCD) long-distance matrix element (LDME) for a heavy-quark pair in an $S$-wave, color-octet state to fragment into a heavy-quark pair in a color-singlet state of arbitrary orbital angular momentum. The NRQCD factorization conjecture for the universality of the LDME requires that infrared divergences that it contains be independent of the direction of the Wilson line that appears in its definition. We find this to be the case in our calculation. The results of our calculation differ in some respects from those of a previous calculation that was carried out by Nayak, Qiu, and Sterman using light-cone methods. We have identified the sources of some of these differences. The results of both calculations are consistent with the NRQCD factorization conjecture. However, the general principle that underlies this confirmation of NRQCD factorization at two-loop order has yet to be revealed.

   hep-phPRD(2020)·11 citations
4. 04*

   Flavour and CP predictions from orbifold compactification

   Francisco J. de Anda🇲🇽 · José W. F. Valle🇪🇸 · Carlos A. Vaquera-Araujo🇲🇽

   We propose a theory for fermion masses and mixings in which an $A_4$ family symmetry arises naturally from a six-dimensional spacetime after orbifold compactification. The flavour symmetry leads to the successful "golden" quark-lepton unification formula. The model reproduces oscillation parameters with good precision, giving sharp predictions for the CP violating phases of quarks and leptons, in particular ${\delta }^{\ell }\simeq +268^{\circ }$. The effective neutrinoless double-beta decay mass parameter is also sharply predicted as $⟨m_{\beta \beta }⟩\simeq 2.65meV$.

   hep-phPLB(2020)·15 citations
5. 05*

   An Introduction to Particle Dark Matter

   Stefano Profumo🇺🇸 · Leonardo Giani🇧🇷 · Oliver F. Piattella🇧🇷

   We review the features of Dark Matter as a particle, presenting some old and new instructive models, and looking for their physical implications in the early universe and in the process of structure formation. We also present a schematic of Dark Matter searches and introduce the most promising candidates to the role of Dark Matter particle.

   hep-phastro-ph.GAhep-thUniverse(2019)·108 citations
6. 06*

   Velocity-dependent self-interacting dark matter from thermal freeze-out and tests in direct detections

   Lian-Bao Jia🇨🇳

   A small fraction of millicharged dark matter (DM) is considered in the literature to give an interpretation about the enhanced 21-cm absorption at the cosmic dawn. Here we focus on the case that the main component of DM is self-interacting dark matter (SIDM), motivated by the small scale problems. For self interactions of SIDM being compatible from dwarf to cluster scales, velocity-dependent self interactions mediated by a light scalar $\varphi$ is considered. To fermionic SIDM $\Psi$, the main annihilation mode $\Psi \bar{\Psi }\to \varphi \varphi$ is a $p-$wave process. The thermal transition of SIDM $\rightleftarrows \varphi \rightleftarrows$ standard model (SM) particles in the early universe sets a lower bound on couplings of $\varphi$ to SM particles, which has been excluded by DM direct detections, and here we consider SIDM in the thermal equilibrium via millicharged DM. For $m_{\varphi }>$ twice millicharged DM mass, $\varphi$ could decay quickly and avoid excess energy injection to the big bang nucleosynthesis. Thus, the $\varphi -$SM particle couplings could be very tiny and evade DM direct detections. The picture of weakly interacting massive particle (WIMP)-nucleus scattering with contact interactions fails for SIDM-nucleus scattering with a light mediator, and a method is explored in this paper, with which a WIMP search result can be converted into the hunt for SIDM in direct detections.

   hep-phastro-ph.COhep-exEPJC(2020)·2 citations
7. 07*

   A systematically study of thermal width of heavy quarkonia in a finite temperature magnetized background from holography

   Sheng-Qin Feng🇨🇳 · Yan-Qing Zhao🇨🇳 · Xun Chen🇨🇳

   By simulating the finite temperatures magnetized background in the RHIC and LHC energies, we systematically study the characteristics of thermal widths and potentials of heavy quarkonia. It is found that the magnetic field has less influence on the real potential, but has a significant influence on the imaginary potential, especially in the low deconfined temperature. Extracted from the effect of thermal worldsheet fluctuations about the classical configuration, the thermal width of ${\rm Y}(1s)$ in the finite temperature magnetized background is investigated. It is found that at the low deconfined temperature the magnetic field can generate a significant thermal fluctuation of the thermal width of ${\rm Y}(1s)$, but with the increase of temperature, the effect of magnetic field on the thermal width becomes less important, which means the effect of high temperature completely exceeds that of magnetic field and magnetic field become less important at high temperature. The thermal width decreases with the increasing rapidity at the finite temperature magnetized background. It is also observed that the effect of the magnetic field on the thermal width when dipole moving parallel to the magnetic field direction are larger than that moving perpendicular to the magnetic field direction, which implies that the magnetic field tends to enhance thermal fluctuation when dipole moving parallel to the direction of magnetic field. The thermal width of ${\rm Y}(1S)$ hardly changes with the increasing temperature when dipole moving perpendicular to the magnetic field. But when dipole moving parallel to the magnetic field, the thermal width at low temperature is obviously larger than that at high temperature.

   hep-phPRD(2020)·20 citations
8. 08*

   Neutrino oscillations in supernovae: angular moments and fast instabilities

   Lucas Johns🇺🇸 · Hiroki Nagakura🇺🇸 · George M. Fuller🇺🇸 · Adam Burrows🇺🇸

   Recent theoretical work indicates that the neutrino radiation in core-collapse supernovae may be susceptible to flavor instabilities that set in far behind the shock, grow extremely rapidly, and have the potential to profoundly affect supernova dynamics and composition. Here we analyze the nonlinear collective oscillations that are prefigured by these instabilities. We demonstrate that a zero-crossing in $n_{{\nu }_e}-n_{{\bar{\nu }}_e}$ as a function of propagation angle is not sufficient to generate instability. Our analysis accounts for this fact and allows us to formulate complementary criteria. Using Fornax simulation data, we show that fast collective oscillations qualitatively depend on how forward-peaked the neutrino angular distributions are.

   hep-phastro-ph.HEPRD(2020)·142 citations
9. 09*

   Thermodynamics and statistical physics of quasiparticles within the quark-gluon plasma model

   V. Dzhunushaliev🇰🇿 · V. Folomeev🇰🇿 · T. Ramazanov🇰🇿 · T. Kozhamkulov🇰🇿

   We consider thermodynamic properties of a quark-gluon plasma related to quasiparticles having the internal structure. For this purpose, we employ a possible analogy between quantum chromodynamics and non-Abelian Proca-Dirac-Higgs theory. The influence of characteristic sizes of the quasiparticles on such thermodynamic properties of the quark-gluon plasma like the internal energy and pressure is studied. Sizes of the quasiparticles are taken into account in the spirit of the van der Waals equation but we take into consideration that the quasiparticles have different sizes, and the average value of these sizes depends on temperature. It is shown that this results in a change in the internal energy and pressure of the quark-gluon plasma. Also, we show that, when the temperature increases, the average value of characteristic sizes of the quasiparticles increases as well. This leads to the occurrence of a phase transition at the temperature at which the volume occupied by the quasiparticles is compared with the volume occupied by the plasma.

   hep-phhep-thMod.Phys.Lett.A(2020)·2 citations
10. 10*

    Blois 2019: highlights and outlook

    Graciela B. Gelmini🇺🇸

    This is an idiosyncratic account of the main results presented at the 31st Rencontres de Blois, which took place from June 2nd to June 7th, 2019 in the Castle of Blois, France.

    hep-phastro-ph.CO0 citations
11. 11*

    The effects of $O({\alpha }^2)$ initial state QED corrections to $e^{+}{e}^{-}\to {\gamma }^{\ast }/Z^{\ast }$ at very high luminosity colliders

    J. Blümlein🇩🇪 · A. De Freitas🇩🇪 · C.G. Raab🇦🇹 · K. Schönwald🇩🇪

    We present numerical results on the recently completed $O({\alpha }^2)$ initial state corrections to the process $e^{+}{e}^{-}\to {\gamma }^{\ast }/Z^{\ast }$, which is a central process at past and future high energy and high luminsoity colliders for precision measurements of the properties of the $Z$-boson, the Higgs boson, and the top quark. We observe differences to an earlier result \cite{Berends:1987ab} in the non-logarithmic contributions at $O({\alpha }^2)$. The new result leads to a 4 MeV shift in the $Z$ width considering the lower end $s_0=4m_{\tau }^2$ of the radiation region, which is larger than the present accuracy. We present predictions on the radiative corrections to the central processes $e^{+}{e}^{-}\to {\gamma }^{\ast }/Z^{\ast }$, $e^{+}{e}^{-}\to ZH$ and $e^{+}{e}^{-}\to t\overline{t}$ planned at future colliders like the ILC, CLIC, Fcc\_ee and CEPC to measure the mass and the width of the $Z$ boson, the Higgs boson and the top quark, for which the present corrections are significant.

    hep-phhep-exPLB(2020)·16 citations
12. 12*

    Non-renormalization and operator mixing via on-shell methods

    Zvi Bern🇺🇸 · Julio Parra-Martinez🇺🇸 · Eric Sawyer🇺🇸

    Using on-shell methods, we present a new perturbative non-renormalization theorem for operator mixing in massless four-dimensional quantum field theories. By examining how unitarity cuts of form factors encode anomalous dimensions we show that longer operators are often restricted from renormalizing shorter operators at the first order where there exist Feynman diagrams. The theorem applies quite generally and depends only on the field content of the operators involved. We apply our theorem to operators of dimension five through seven in the Standard Model Effective Field Theory, including examples of nontrivial zeros in the anomalous-dimension matrix at one through four loops. The zeros at two and higher loops go beyond those previously explained using helicity selection rules. We also include explicit sample calculations at two loops.

    hep-phhep-thPRL(2020)·77 citations
13. 13*

    Electric dipole moments of neutron and heavy quarks in the B-L symmetric MSSM

    Jin-Lei Yang🇨🇳 · Tai-Fu Feng🇨🇳 · Sheng-Kai Cui🇨🇳 · Chang-Xin Liu🇨🇳 · Wei Li🇨🇳 · Hai-Bin Zhang🇨🇳

    The searching for the electric dipole moments (EDMs) of neutron ($d_n$), $b$ quark ($d_b$) and $c$ quark ($d_c$) gives strict upper bounds on these quantities. And recently, new upper bounds on $d_b$, $d_c$ are obtained by the strict limit on $d_n$. The models of new physics (NP) with additional CP-violating (CPV) sources are constrained strictly by these EDMs. In this work, we focus on the CPV effects on these EDMs in the minimal supersymmetric extension (MSSM) of the SM with local $B-L$ gauge symmetry (B-LSSM). The contributions from one-loop and some two-loop diagrams to the quark EDM are given in general form, which can also be used in the calculation of quark EDM in other models of NP. Considering the constrains from updated experimental data, the numerical results show that the two-loop corrections can make important contributions to these EDMs. Compared with the MSSM, the effects of new CPV phases and new parameters in the B-LSSM on these EDMs are also explored.

    hep-phJHEP(2020)·15 citations
14. 14*

    Analytic Form of the Three-loop Four-gluon Scattering Amplitudes in Yang-Mills Theory

    Qingjun Jin🇨🇳 · Hui Luo🇨🇳

    We present analytic forms of three-loop four-gluon planar amplitudes in pure Yang-Mills theory in this letter. Gauge invariant bases and a set of proper master integrals are chosen such that the amplitudes are explicitly invariant under cyclic permutations of external particles. The $D$-dimensional unitarity method and integration-by-parts reductions with cut conditions are performed to determine the coefficients of the master integrals. Helicity amplitudes in the conventional dimension regularization scheme are obtained by setting gauge invariant bases to helicity configurations. After renormalizing the ultraviolet divergences, remaining divergences of the amplitudes agree with known infrared divergence structures exactly. Our results provide an essential piece of three-loop amplitudes required for the ${\mathrm{N}}^3\mathrm{LO}$ order corrections to the production of two jets at hadron colliders.

    hep-ph23 citations
15. 15*

    New Physics Interpretations with GAMBIT

    Peter Athron (for the GAMBIT Collaboration)🇦🇺

    I present recent results from the Global and Modular Beyond-the-Standard-Model Inference Tool (GAMBIT) collaboration. Global fits with GAMBIT have been carried out on a variety of models including supersymmetric models, scalar singlet dark matter, fermionic and vector Higgs portal dark matter and axions. Here I focus on a recent GAMBIT study interpreting collider constraints on electroweakinos (arXiv:1809.02097). We show that when the neutralinos and charginos are the only light states of the MSSM, there are scenarios which evade LHC constraints for any mass of the lightest neutralino and the lightest chargino, i.e. the profile likelihood shows no constraint in this plane when one only considers the possibility of excluding new physics. Intriguingly, in addition we also find that excesses in the data can lead to closed confidence level contours, indicating a preference for light neutralinos and charginos over the Standard Model. We find the excess has a local significance of 3.3 sigma when combining ATLAS and CMS 13 TeV searches, but this drops to 2.9 sigma when including 8 TeV searches as well.

    hep-phPoS(2020)·1 citation
16. 16*

    Top FCNC induced by a Z' boson

    Sungwoong Cho🇰🇷 · P. Ko🇰🇷 · Jungil Lee🇰🇷 · Yuji Omura🇯🇵 · Chaehyun Yu🇰🇷

    We consider a Z' model where the Z' boson couples only to up and top quarks. As a simple setup, one can consider a family-dependent $U(1{)}^{\prime }$ symmetry, under which only right-handed up-type quarks are charged. After symmetry breaking, the right-handed quarks mix with each other and top flavor-changing neutral currents (FCNCs) mediated by the Z' boson can be generated at tree level. We take into account several processes to probe the top FCNCs, and find that the same sign top quark pair production or the triple top quark production is the most capable of testing the top FCNCs. We also consider a few non-FCNC processes to probe the Z' boson, for example, dijet production at the LHC.

    hep-phPRD(2020)·9 citations
17. 17*

    Contribution of neutral pseudoscalar mesons to $a_{\mu }^{HLbL}$ within a Schwinger-Dyson equations approach to QCD

    K. Raya🇨🇳 · A. Bashir🇲🇽 · P. Roig🇲🇽

    A continuum approach to Quantum Chromodynamics (QCD), based upon Schwinger-Dyson (SD) and Bethe-Salpeter (BS) equations, is employed to provide a tightly constrained prediction for the ${\gamma }^{\ast }{\gamma }^{\ast }\to \{{\pi }^0,\eta ,{\eta }^{\prime },{\eta }_c,{\eta }_b\}$ transition form factors (TFFs) and their corresponding pole contribution to the hadronic light-by-light (HLbL) piece of the anomalous magnetic moment of the muon ($a_{\mu }$). This work relies on a practical and well-tested quark-photon vertex Ansatz approach to evaluate the TFFs for arbitrary space-like photon virtualities, in the impulse approximation. The numerical results are parametrized meticulously, ensuring a reliable evaluation of the HLbL contributions to $a_{\mu }$. We obtain: $a_{\mu }^{{\pi }^0-\text{pole}}=(6.14\pm 0.21)\times 10^{-10}$, $a_{\mu }^{\eta -\text{pole}}=(1.47\pm 0.19)\times 10^{-10}$, $a_{\mu }^{{\eta }^{\prime }-\text{pole}}=(1.36\pm 0.08)\times 10^{-10}$, yielding a total value of $a_{\mu }^{{\pi }^0+\eta +{\eta }^{\prime }-\text{pole}}=(8.97\pm 0.48)\times 10^{-10}$, compatible with contemporary determinations. Notably, we find that $a_{\mu }^{{\eta }_c+{\eta }_b-\text{pole}}\approx a_{\mu }^{{\eta }_c-\text{pole}}=(0.09\pm 0.01)\times 10^{-10}$, which might not be negligible once the percent precision in the computation of the light pseudoscalars is reached.

    hep-phPRD(2020)·64 citations
18. 18*

    Mass structure and pressure forces inside the nucleon

    Cédric Lorcé (Ecole Polytechnique and CNRS)🇫🇷

    We summarize recent works on the question of the nucleon mass decomposition and the 2D relativistic distribution of pressure forces on the light front. All these mechanical properties are encoded in the energy-momentum tensor of the system which can be constrained using various types of high-energy lepton-nucleon scatterings. Some further developments for targets with spin $>1/2$ are also reported.

    hep-phnucl-th1 citation
19. 19*

    Charmonium spectroscopy motivated by general features of pNRQCD

    Raghav Chaturvedi🇮🇳 · Ajay Kumar Rai🇮🇳

    Mass spectrum of charmonium is computed in the framework of potential non-relativistic quantum chromodynamics. \textit{O}$(1/m)$ and \textit{O}$(1/m^2)$ relativistic corrections to the Cornell potential and spin-dependent potential have been added, and is solved numerically. New experimentally observed and modified positive and negative parity states like $\mathbf{\psi }(4230)$, $\mathbf{\psi }(4260)$, $\mathbf{\psi }(4360)$, $\mathbf{\psi }(4390)$, $\mathbf{\psi }(4660)$, ${\mathbf{\chi }}_{c1}(4140)$ and ${\mathbf{\chi }}_{c1}(4274)$ near open-flavor threshold have also been studied. We explain them as admixtures of S-D wave states and P-wave states. Apart from these states, some other states like $X(3915)$, ${\mathbf{\chi }}_{c1}(3872)$, $\mathbf{\psi }(3770)$ and $\mathbf{\psi }(4160)$ have been identified as $2^3{P}_0$, $2^3{P}_1$, $1^3{D}_1$ and $2^3{D}_1$ states. Subsequently, the electromagnetic transition widths and $\gamma \gamma$, $e^{+}{e}^{-}$, light hadron and $\gamma \gamma \gamma$ decay widths of several states are calculated at various leading orders. All the calculated results are compared with experimental and results from various theoretical models.

    hep-phInt.J.Theor.Phys.(2020)·32 citations
20. 20*

    Using Machine Learning to disentangle LHC signatures of Dark Matter candidates

    C. K. Khosa🇬🇧 · V. Sanz🇬🇧 · M. Soughton🇬🇧

    We study the prospects of characterising Dark Matter at colliders using Machine Learning (ML) techniques. We focus on the monojet and missing transverse energy (MET) channel and propose a set of benchmark models for the study: a typical WIMP Dark Matter candidate in the form of a SUSY neutralino, a pseudo-Goldstone impostor in the shape of an Axion-Like Particle, and a light Dark Matter impostor whose interactions are mediated by a heavy particle. All these benchmarks are tensioned against each other, and against the main SM background ($Z$+jets). Our analysis uses both the leading-order kinematic features as well as the information of an additional hard jet. We explore different representations of the data, from a simple event data sample with values of kinematic variables fed into a Logistic Regression algorithm or a Fully Connected Neural Network, to a transformation of the data into images related to probability distributions, fed to Deep and Convolutional Neural Networks. We also study the robustness of our method against including detector effects, dropping kinematic variables, or changing the number of events per image. In the case of signals with more combinatorial possibilities (events with more than one hard jet), the most crucial data features are selected by performing a Principal Component Analysis. We compare the performance of all these methods, and find that using the 2D images of the combined information of multiple events significantly improves the discrimination performance.

    hep-phSciPost Phys.(2021)·23 citations
21. 21*

    Bottomonium spectrum in the relativistic flux tube model

    Bing Chen🇨🇳 · Ailin Zhang🇨🇳 · Jin He🇨🇳

    The bottomonium spectrum is far from being established. The structures of higher vector states, including the ${\rm Y}(10580)$, ${\rm Y}(10860)$, and ${\rm Y}(11020)$ states, are still in dispute. In addition, whether the ${\rm Y}(10750)$ signal which was recently observed by the Belle Collaboration is a normal $b\bar{b}$ state or not should be examined. Faced with such a situation, we carried out a systematic investigation of the bottomonium spectrum in the scheme of the relativistic flux tube (RFT) model. A Chew-Frautschi like formula was derived analytically for the spin average mass of bottomonium states. We further incorporated the spin-dependent interactions and obtained a complete bottomonium spectrum. We found that the most established bottomonium states can be explained in the RFT scheme. The ${\rm Y}(10750)$, ${\rm Y}(10860)$, and ${\rm Y}(11020)$ could be predominantly the $3^3{D}_1$, $5^3{S}_1$, and $4^3{D}_1$ states, respectively. Our predicted masses of $1F$ and $1G$ $b\bar{b}$ states are in agreement with the results given by the method of lattice QCD, which can be tested by experiments in future. We also compared the RFT model with the quark potential model in detail. The differences of these two kinds of models were discussed.

    hep-phhep-exPRD(2020)·43 citations
22. 22*

    Spectroscopy and decay properties of bottomonium using instanton induced potential from QCD vacuum

    Bhoomika Pandya🇮🇳 · Manan Shah🇮🇳 · P C Vinodkumar🇮🇳

    Ground state and radial excitation mass spectra of bottomonium states are computed using the Instanton Induced $q\bar{q}$ Potential obtained from Instanton Liquid Model for QCD vacuum. The Schrodinger equation is solved for two body problem using variational method. Hyperfine interactions are incorporated to remove the degeneracy between spin singlet and spin triplet states of $S$ wave masses. Spin-orbit and tensor interactions through one gluon exchange has been added to the spin average masses of P and D wave states. The vector decay constants and pseudoscalar decay constants are also estimated using the Van Royan Weiskopff formula within non-relativistic limit. The di-leptonic, di-gamma, di-gluon decays of the bottomonium states are predicted without and with QCD corrections up to the lowest order using numerical values of the wave function at origin. Tri-gluon decays of respective $S$, $P$ and $D$ states are also studied. Other annihilation decay channels of bottomonium states into $\gamma gg$ , $\gamma \gamma \gamma$ , $q\bar{q}+g$ are also computed. The radiative transitions of first order like electric dipole transitions (E1) and magnetic dipole transitions (M1) are estimated. Our estimations of the mass spectra and decay properties for bottomonium found to be in excellent agreement with the average experimental values reported by particle data group.

    hep-ph0 citations
23. 23*

    Strong decays of the higher excited ${\Lambda }_Q$ and ${\Sigma }_Q$ baryons

    Qi-Fang Lü🇨🇳 · Xian-Hui Zhong🇨🇳

    In this work, we preform a systematic study of the strong decays for the higher singly heavy baryon resonances ${\Lambda }_Q(3S)$, ${\Lambda }_Q(2P)$, ${\Lambda }_Q(2D)$, ${\Lambda }_Q(1F)$, ${\Sigma }_Q(3S)$, ${\Sigma }_Q(2P)$, ${\Sigma }_Q(2D)$, and ${\Sigma }_Q(1F)$ within the ${}^3{P}_0$ model. Our results show that most of the $\lambda -$mode higher excited ${\Lambda }_Q$ and ${\Sigma }_Q$ states have a relatively narrow width, and mainly decay into two-body final states with one heavy meson plus one light baryon. Our calculations provide abundant theoretical information and demonstrate the general feature for these higher states, which may be valuable for future experimental searches and establishing the singly heavy baryon spectrum.

    hep-phhep-exnucl-thPRD(2020)·36 citations
24. 24*

    No chiral light bending by clumps of axion-like particles

    Diego Blas🇬🇧 · Andrea Caputo🇪🇸 · Mikhail M. Ivanov🇺🇸 · Laura Sberna🇨🇦

    We study the propagation of light in the presence of a parity-violating coupling between photons and axion-like particles (ALPs). Naively, this interaction could lead to a split of light rays into two separate beams of different polarization chirality and with different refraction angles. However, by using the eikonal method we explicitly show that this is not the case and that ALP clumps do not produce any spatial birefringence. This happens due to non-trivial variations of the photon's frequency and wavevector, which absorb time-derivatives and gradients of the ALP field. We argue that these variations represent a new way to probe the ALP-photon couping with precision frequency measurements.

    hep-phastro-ph.COhep-thPhys.Dark Univ.(2020)·27 citations
25. 25*

    First results of the KATRIN neutrino mass experiment and their consistency with an exotic $3+3$ model

    Robert Ehrlich🇺🇸

    Although the first results of the KATRIN neutrino mass experiment are consistent with a new improved upper limit of 1.1 eV for the effective mass of the electron neutrino, surprisingly they are also consistent with an exotic model of the neutrino masses put forward in 2013 that includes one tachyonic mass state doublet having $m^2\sim -0.2$ keV${}^2$. A definitive conclusion on the validity of the model should be possible after less than one year of KATRIN data-taking.

    hep-phLHEP(2019)·3 citations
26. 26*

    Sum Rules for Massive Spin-2 Kaluza-Klein Elastic Scattering Amplitudes

    R. Sekhar Chivukula🇺🇸 · Dennis Foren🇺🇸 · Kirtimaan A Mohan🇺🇸 · Dipan Sengupta🇺🇸 · Elizabeth H. Simmons🇺🇸

    It has recently been shown explicitly that the high-energy scattering amplitude of the longitudinal modes of massive spin-2 Kaluza Klein states in compactified 5-dimensional gravity, which would naively grow like O(s^5), grow only like O(s). Since the individual contributions to these amplitudes do grow like O(s^5), the required cancellations between these individual contributions result from intricate relationships between the masses of these states and their couplings. Here we report the explicit form of these sum-rule relationships which ensure the necessary cancellations for elastic scattering of spin-2 Kaluza Klein states in a Randall-Sundrum model. We consider an Anti-de-Sitter space of arbitrary curvature, including the special case of a toroidal compactification in which the curvature vanishes. The sum rules demonstrate that the cancellations at O(s^5) and O(s^4) are generic for a compact extra dimension, and arise from the Sturm-Liouville structure of the eigenmode system in the internal space. Separately, the sum rules at O(s^3) and O(s^2) illustrate the essential role of the radion mode of the extra-dimensional metric, which is the dynamical mode related to the size of the internal space.

    hep-phhep-thPRD(2019)·26 citations
27. 27*

    Two-Photon-Exchange effects in $ep\to en{\pi }^{+}$ and their corrections to separated cross sections ${\sigma }_{\text{L,T,LT,TT}}$ at small $-t$

    Hui-Yun Cao🇨🇳 · Hai-Qing Zhou🇨🇳

    In this work, the two-photon-exchange (TPE) effects in $ep\to en{\pi }^{+}$ at small $-t$ are discussed within a hadronic model. Under the pion dominance approximation the TPE contribution to the amplitude can be described by a scalar function in the limit $m_e\to 0$. The TPE contributions to the amplitude and the unpolarized differential cross section are both estimated when only the elastic intermediate state is considered. We find that the TPE corrections to the unpolarized differential cross section are about from $-4\%$ to $-20\%$ at $Q^2=1$--$1.6$ GeV${}^2$. After considering the TPE corrections to the experimental data sets of unpolarized differential cross section, we analyze the TPE corrections to the separated cross sections ${\sigma }_{\text{L,T,LT,TT}}$. We find that the TPE corrections (at $Q^2=1$--$1.6$ GeV${}^2$) to ${\sigma }_{\text{L}}$ are about from $-10\%$ to $-30\%$, to ${\sigma }_{\text{T}}$ are about $20\%$, and to ${\sigma }_{\text{LT,TT}}$ are much larger. By these analysis, we conclude that the TPE contributions in $ep\to en{\pi }^{+}$ at small $-t$ are important to extract the separated cross sections ${\sigma }_{\text{L,T,LT,TT}}$ and the electromagnetic magnetic form factor of ${\pi }^{+}$ in the experimental analysis.

    hep-phnucl-exnucl-thPRC(2020)·5 citations
28. 28*

    Cosmological Phase Transition of Spontaneous Confinement

    Kaustubh Agashe🇺🇸 · Peizhi Du🇺🇸 · Majid Ekhterachian🇺🇸 · Soubhik Kumar🇺🇸 · Raman Sundrum🇺🇸

    The dynamics of a cosmological (de)confinement phase transition is studied in nearly conformally invariant field theories, where confinement is predominantly spontaneously generated and associated with a light "dilaton" field. We show how the leading contribution to the transition rate can be computed within the dilaton effective theory. In the context of Composite Higgs theories, we demonstrate that a simple scenario involving two renormalization-group fixed points can make the transition proceed much more rapidly than in the minimal scenario, thereby avoiding excessive dilution of matter abundances generated before the transition. The implications for gravitational wave phenomenology are discussed. In general, we find that more (less) rapid phase transitions are associated with weaker (stronger) gravitational wave signals. The various possible features of the strongly coupled composite Higgs phase transition discussed here can be concretely modeled at weak coupling within the AdS/CFT dual Randall-Sundrum extra-dimensional description, which offers important insights into the nature of the transition and its theoretical control. These aspects will be presented in a companion paper.

    hep-phhep-thJHEP(2020)·83 citations
29. 29*

    Probing loop effects in wrong-sign Yukawa region of 2HDM

    Wei Su🇦🇺

    In the framework of 2HDM, we explore the wrong-sign Yukawa region with direct and indirect searches up to one-loop level. The direct searches include the latest $H/A\to f\bar{f},VV,Vh,hh$ reports at current LHC, and the study of indirect Higgs precision measurements works with current LHC, future HL-LHC and CEPC. At tree level of Type-II 2HDM, for degenerate heavy Higgs mass $m_A=m_H=m_{H^{\pm }}<800$ GeV, the wrong-sign Yukawa regions are excluded largely except for the tiny allowed region around $\cos (\beta -\alpha )\in (0.2,0.3)$ under the combined constraints. The excluded region is also nearly independent of parameter $m_{12}$ or $\lambda v^2=m_A^2-m_{12}^2/(\sin \beta \cos \beta )$. The situation changes a lot after including loop corrections to the indirect searches, for example $m_A=800$ GeV, the region with $\lambda v^2<0$ will be stronger constrained to be totally excluded. Whilst $\lambda v^2>0$ would get larger survived wrong-sign region, such as $\cos (\beta -\alpha )\in (0,0.3)$ for $\sqrt{\lambda v^2}=400$ GeV, under combined restrictions.

    hep-phEPJC(2021)·17 citations
30. 30*

    Internal Reduction method for computing Feynman Integrals

    Costas G. Papadopoulos🇬🇷 · Christopher Wever🇩🇪

    A new approach to compute Feynman Integrals is presented. It relies on an integral representation of a given Feynman Integral in terms of simpler ones. Using this approach, we present, for the first time, results for a certain family of non-planar five-point two-loop Master Integrals with one external off-shell particle, relevant for instance for $H+2$ jets production at the LHC, in both Euclidean and physical kinematical regions.

    hep-phhep-thJHEP(2020)·33 citations
31. 31*

    Combinatorial Superstatistics for Soft QCD

    Mikael Mieskolainen🇫🇮

    High energy diffraction and soft QCD span exciting final state topologies and fluctuations which have not yet been measured or characterized in a fully exhaustive way. In this work, we go beyond the standard measures and formulate a new framework to generalize rapidity gap counting with emphasis on abstract structure, fiducial observables, experimental limitations and factorizing model dependence. The construction is based on a higher dimensional Bernoulli vector statistics with a combinatorial incidence algebra structure, independent of the underlying field theory. This is the first experimentally feasible framework designed to probe the seemingly arcane sign alternating scattering amplitude cutting rules of style Abramovski-Gribov-Kancheli, rules being of interest in Regge theory, perturbative QCD and even in stringy black hole calculus. As an additional novel show case, we pose, construct and solve a highly related combinatorial stochastic superposition Poisson inverse problem using the Möbius inversion theorem.

    hep-phhep-ex4 citations
32. 32*

    Different space-time freeze-out picture -- an explanation of different $\Lambda$ and $\bar{\Lambda }$ polarization?

    O. Vitiuk🇺🇦 · L. Bravina🇳🇴 · E. Zabrodin🇳🇴

    Thermal vorticity in non-central Au+Au collisions at energies $7.7\le \sqrt{s}\le 62.4$ GeV is calculated within the UrQMD transport model. Tracing the $\Lambda$ and $\bar{\Lambda }$ hyperons back to their last interaction point we were able to obtain the temperature and the chemical potentials at the time of emission by fitting the extracted bulk characteristics of hot and dense medium to statistical model of ideal hadron gas. Then the polarization of both hyperons was calculated. The polarization of $\Lambda$ and $\bar{\Lambda }$ increases with decreasing energy of nuclear collisions. The stronger polarization of $\bar{\Lambda }$ is explained by the different space-time distributions of $\Lambda$ and $\bar{\Lambda }$ and by different freeze-out conditions of both hyperons.

    hep-phnucl-exnucl-thPLB(2020)·81 citations
33. 33*

    GRANIITTI: A Monte Carlo Event Generator for High Energy Diffraction

    Mikael Mieskolainen🇫🇮

    We describe the physics and computational power of GRANIITTI Monte Carlo event generator, a new fully multithreaded engine designed for high energy diffraction, written in modern C++. The emphasis is especially on the low-mass domain of central exclusive processes of the S-matrix, where exotic QCD phenomena such as glueballs are expected and holographic dualities with gravity may be tested. The generator includes photon-photon, photon-pomeron, pomeron-pomeron, Durham QCD model and Tensor pomeron model type scattering amplitudes and advanced spin analysis tools. The generator combines a full parametric resonance spectrum with continuum interference and forward + central spin correlations together with event-by-event eikonal screening loop and forward proton excitation kinematics. We demonstrate the state-of-the-art capabilities and show how the enigmatic `glueball filter' observable is driven by spin polarization.

    hep-phhep-ex14 citations
34. 34*

    Aspects of Nonlinear Effect on Black Hole Superradiance

    Hajime Fukuda🇺🇸 · Kazunori Nakayama🇯🇵

    Under some conditions, light boson fields grow exponentially around a rotating black hole, called the superradiance instability. We discuss effects of nonlinear interactions of the boson on the instability. In particular, we focus on the effect of the particle production and show that the growth of the boson cloud may be saturated much before the black hole spin is extracted by the boson cloud, while the nonlinear interactions also induce the boson emission. For application, we revisit the superradiant instability of the standard model photon, axion and hidden photon.

    hep-phgr-qcJHEP(2020)·89 citations
35. 35*

    Quantum Tomography Measures Entanglement in Collider Reactions

    John C. Martens🇺🇸 · John P. Ralston🇺🇸 · Daniel Tapia Takaki🇺🇸

    Entanglement in high energy and and nuclear reactions is receiving great attention. A proper description of these reactions uses density matrices, and the express of entanglement in terms of {\it separability}. Quantum tomography bypasses field-theoretic formalism to determine density matrices in terms of experimental observables. We review recent work applying quantum tomography to practical experimental data analysis. We discuss the relation between separability, as defined in quantum information science, and factorization, as defined in high energy physics. When factorization applies, it comes from using separable probes, which tomographically determine separable projections of entangled density matrices.

    hep-phnucl-thquant-ph1 citation
36. 36*

    Light Dark Matter from Entropy Dilution

    Jared A. Evans🇺🇸 · Akshay Ghalsasi🇺🇸 · Stefania Gori🇺🇸 · Michele Tammaro🇺🇸 · Jure Zupan🇺🇸

    We show that a thermal relic which decouples from the standard model (SM) plasma while relativistic can be a viable dark matter (DM) candidate, if the decoupling is followed by a period of entropy dilution that heats up the SM, but not the dark sector. Such diluted hot relics can be as light as a keV, while accounting for the entirety of the DM, and not conflicting with cosmological and astrophysical measurements. The requisite dilution can be achieved via decays of a heavy state that dominates the energy budget of the universe in the early matter dominated era. The heavy state decays into the SM particles, heats up the SM plasma, and dilutes the hidden sector. The interaction required to equilibrate the two sectors in the early universe places a bound on the maximum possible dilution as a function of the decoupling temperature. As an example of diluted hot relic DM we consider a light Dirac fermion with a heavy dark photon mediator. We present constraints on the model from terrestrial experiments (current and future), astrophysics, and cosmology.

    hep-phJHEP(2020)·47 citations
37. 37*

    Polarised Amplitudes and Soft-Virtual Cross Sections for $b\bar{b}\to ZH$ at NNLO in QCD

    Taushif Ahmed🇩🇪 · A.H. Ajjath · Long Chen🇩🇪 · Prasanna K. Dhani🇮🇹 · Pooja Mukherjee🇮🇳 · V. Ravindran🇮🇳

    Production of the Higgs boson, $H$ in association with a massive vector boson, $V$, i.e., the $VH$ process, plays an important role in the explorations of Higgs physics at the Large Hadron Collider, both for a precise study of Higgs' Standard Model couplings and for probing New Physics. In this publication we present the two-loop corrections in massless quantum chromodynamics (QCD) to the amplitude of the Higgs production associated with a $Z$ boson via the bottom quark-antiquark annihilation channel with a non-vanishing bottom-quark Yukawa coupling, which is a necessary ingredient of the full next-to-next-to-leading-order QCD corrections to the $VH$ process in the five-flavour scheme. The computation is performed by projecting the D-dimensional scattering amplitude directly onto an appropriate set of Lorentz structures related to the linear polarisation states of the $Z$ boson. We provide analytic expressions of the complete set of renormalised polarised amplitudes in terms of polylogarithms of maximum weight four. To give an estimation of the size of contributions from amplitudes considered in this work, we compute numerically the resulting cross sections under the soft-virtual approximation. We also take the opportunity to make a dedicated discussion regarding an interesting subtlety appearing in the conventional form factor decomposition of amplitudes involving axial currents regularised in D dimensions.

    hep-phhep-thJHEP(2020)·31 citations
38. 38*

    Bounds on the non-standard $W^{+}{W}^{-}\gamma$ couplings at the LHeC and the FCC-he

    M. Koksal🇹🇷 · A. A. Billur🇹🇷 · A. Gutierrez-Rodriguez🇲🇽 · M. A. Hernandez-Ruiz🇲🇽

    We examine the potential of the $e^{-}p\to e^{-}{\gamma }^{\ast }p\to e^{-}{W}^{-}{q}^{\prime }X$ (${\gamma }^{\ast }$ is Weizsacker-Willams photon) reaction to probe the non-standard $W^{+}{W}^{-}\gamma$ couplings at the Large Hadron electron Collider (LHeC) and the Future Circular Collider-hadron electron (FCC-he). We find $95\%$ confidence level bounds on the anomalous coupling $\Delta {\kappa }_{\gamma }$ and ${\lambda }_{\gamma }$ parameters in the view of effective Lagrangian approach with various values of the integrated luminosity. We assume center-of-mass energies of the electron-proton system $\sqrt{s}=1.30,1.98,7.07,10\mathrm{TeV}$ and luminosities $\mathcal{L}=10-1000\mathrm{f}{\mathrm{b}}^{-1}$. The best limits obtained from the process $e^{-}p\to e^{-}{\gamma }^{\ast }p\to e^{-}{W}^{-}{q}^{\prime }X$ on the anomalous $\Delta {\kappa }_{\gamma }$ and ${\lambda }_{\gamma }$ couplings are $\Delta {\kappa }_{\gamma }=|0.00069|$ and ${\lambda }_{\gamma }=[-0.0099,0.0054]$. These bounds show that the process under consideration is a good prospect for the searching of the non-standard $\Delta {\kappa }_{\gamma }$ and ${\lambda }_{\gamma }$ couplings at the LHeC and the FCC-he. In addition, our results provide complementary information on other results for $\Delta {\kappa }_{\gamma }$ and ${\lambda }_{\gamma }$ couplings.

    hep-phPLB(2020)·21 citations
39. 39*

    Kaon-box contribution to the anomalous magnetic moment of the muon

    Gernot Eichmann🇵🇹 · Christian S. Fischer🇩🇪 · Richard Williams🇩🇪

    We present results for the charged kaon-box contributions to the hadronic light-by-light (HLBL) correction of the muon's anomalous magnetic moment. To this end we determine the kaon electromagnetic form factor within the functional approach to QCD using Dyson-Schwinger and Bethe-Salpeter equations and evaluate the kaon-box contribution as defined in the dispersive approach to HLBL. As an update to previous work we also re-evaluate the charged pion-box contribution taking effects due to isospin breaking into account. Our results are $a_{\mu }^{{\pi }^{\pm }-\text{box}}=-15.7(2)(3)\times 10^{-11}$ and $a_{\mu }^{K^{\pm }-\text{box}}=-0.48(2)(4)\times 10^{-11}$ thus confirming the large suppression of box contributions beyond the leading pion box.

    hep-phhep-latPRD(2020)·166 citations
40. 40*

    A Meta-Analysis Of LHC Results

    Sevim Açıksöz🇹🇷 · Bilal Çark🇹🇷 · Selim Mert Kırpıcı🇹🇷 · Merve Yıldız🇰🇷 · Veysi Erkcan Özcan🇹🇷

    We report the preliminary results of a meta-analysis conducted to examine possible biases in the uncertainty values published in papers by ATLAS and CMS experiments. We have performed this analysis using two independent techniques; a vectoral analysis of the vector graphics files and a bitmap analysis of the raster graphic files of the exclusion plots from various physics searches. In both procedures, the aim is to compute the percentages of the data points scattered within 1-sigma and 2-sigma bands of the plots and verify whether the measured percentages agree with statistical norms assuming unbiased estimations of the uncertainties.

    ↳ hep-exhep-phCan.J.Phys.(2019)·0 citations
41. 41*

    Band-limited Features in the Primordial Power Spectrum Do Not Resolve the Hubble Tension

    MiaoXin Liu🇨🇳 · Zhiqi Huang🇨🇳

    For a standard $\Lambda$CDM universe with a power-law primordial power spectrum, the discrepancy between early- and late-universe measurements of the Hubble constant continued to grow and recently reached $5.3\sigma$. During inflation, local features in the inflationary potential often lead to band-limited features in the primordial power spectrum, hence breaking the power-law assumption in the derivation of the Hubble tension. We investigate whether such inflationary "glitches" can ease the Hubble tension. The recently released \emph{Planck} temperature and polarization data and the 2019 SH0ES+H0LiCOW joint constraint on the Hubble constant are combined to drive a blind Daubechies wavelet signal search in the primordial power spectrum, up to a resolution $\Delta \ln k\sim 0.1$. We find no significant detection of any features beyond power law. With 64 more degrees of freedom injected in the primordial power spectrum, the Hubble tension persists at a $4.9\sigma$ level.

    ↳ astro-ph.COgr-qchep-phhep-thApJ(2020)·15 citations
42. 42*

    Recent Results and Future Plans of the MoEDAL Experiment

    Michael Staelens (On behalf of the MoEDAL Collaboration)🇨🇦

    The Monopole and Exotics Detector at the LHC (MoEDAL) is a pioneering LHC experiment designed to search for anomalously ionizing messengers of new physics such as magnetic monopoles or massive (pseudo-)stable charged particles. These are predicted to exist in a plethora of models beyond the Standard Model. Deployed at Interaction Point 8 (IP8) along the LHC ring, MoEDAL has taken data at centre-of-mass energies of 8 and 13 TeV. Its ground breaking physics program defines over 40 scenarios that yield potentially revolutionary insights into such foundational questions as: are there extra dimensions or new symmetries; what is the mechanism for the generation of mass; does magnetic charge exist; and what is the nature of dark matter? MoEDAL's purpose is to meet such far-reaching challenges at the frontier of the field. We present a summary of the MoEDAL detector and its latest results on magnetic monopole production at the LHC. Afterwards, progress on the physics program & installation of MoEDAL's Apparatus for the detection of Penetrating Particles (MAPP) subdetector will be discussed.

    ↳ hep-exhep-ph18 citations
43. 43*

    Construct ${\alpha }^{\prime }$ corrected or loop corrected solutions without curvature singularities

    Peng Wang🇨🇳 · Houwen Wu🇨🇳 · Haitang Yang🇨🇳 · Shuxuan Ying🇨🇳

    For the bosonic gravi-dilaton system, we provide systematical approaches to construct non-perturbative string cosmological solutions without curvature singularities, which can match the perturbative solution to any order in ${\alpha }^{\prime }$ expansion. When higher order ${\alpha }^{\prime }$ corrections are calculated, they can be straightforwardly plugged in to generate compatible non-perturbative evolutions without curvature singularities. We also give a (phenomenological) map between ${\alpha }^{\prime }$ corrected EOM and loop corrected EOM. This map enables us to easily generate a loop corrected solution from an ${\alpha }^{\prime }$ corrected solution, and vice versa, therefore substantially enlarges the solution space.

    ↳ hep-thgr-qchep-phJHEP(2020)·31 citations
44. 44*

    Hot thermal universe endowed with massive dark vector fields and the Hubble tension

    Luis A. Anchordoqui🇺🇸 · Santiago E. Perez Bergliaffa🇺🇸

    The value of Hubble constant inferred from Planck measurements of anisotropies in the cosmic microwave background is at $4.4\sigma$ tension with direct astronomical measurements at low redshifts. Very recently, it has been conjectured that this discrepancy may be reconciled if a small fraction of the dark matter is described by three mutually orthogonal vector fields of the same mass. We study the thermal description of this model and use the observationally-inferred primordial fractions of baryonic mass in ${}^4\mathrm{He}$ to constrain its phase space. We show that while the sterile vector fields may help to alleviate a little bit the existing tension in the measurements of the Hubble parameter, they cannot eliminate the discrepancy between low- and high-redshift observations.

    ↳ astro-ph.COhep-phPRD(2019)·26 citations
45. 45*

    Precision Measurements of Fundamental Interactions with (Anti)Neutrinos

    R. Petti🇺🇸

    We discuss the main limitations of past neutrino scattering experiments and possible ways to address them in a next-generation program of precision measurements of fundamental interactions with (anti)neutrinos. A reduction of the longstanding precision gap with respect to electron scattering experiments could provide interesting synergies with the existing efforts in the fixed-target, collider, and nuclear physics communities.

    ↳ hep-exhep-phnucl-exnucl-th13 citations
46. 46*

    Differentiable Strong Lensing: Uniting Gravity and Neural Nets through Differentiable Probabilistic Programming

    Marco Chianese🇳🇱 · Adam Coogan🇳🇱 · Paul Hofma🇳🇱 · Sydney Otten🇳🇱 · Christoph Weniger🇳🇱

    Since upcoming telescopes will observe thousands of strong lensing systems, creating fully-automated analysis pipelines for these images becomes increasingly important. In this work, we make a step towards that direction by developing the first end-to-end differentiable strong lensing pipeline. Our approach leverages and combines three important computer science developments: (a) convolutional neural networks, (b) efficient gradient-based sampling techniques, and (c) deep probabilistic programming languages. The latter automatize parameter inference and enable the combination of generative deep neural networks and physics components in a single model. In the current work, we demonstrate that it is possible to combine a convolutional neural network trained on galaxy images as a source model with a fully-differentiable and exact implementation of gravitational lensing physics in a single probabilistic model. This does away with hyperparameter tuning for the source model, enables the simultaneous optimization of nearly one hundred source and lens parameters with gradient-based methods, and allows the use of efficient gradient-based posterior sampling techniques. These features make this automated inference pipeline potentially suitable for processing a large amount of data. By analyzing mock lensing systems with different signal-to-noise ratios, we show that lensing parameters are reconstructed with percent-level accuracy. More generally, we consider this work as one of the first steps in establishing differentiable probabilistic programming techniques in the particle astrophysics community, which have the potential to significantly accelerate and improve many complex data analysis tasks.

    ↳ astro-ph.COastro-ph.GAastro-ph.IMhep-phMNRAS(2020)·36 citations
47. 47*

    Trans-Planckian Censorship Conjecture and Non-thermal post-inflationary history

    Mansi Dhuria🇮🇳 · Gaurav Goswami🇮🇳

    The recently proposed Trans-Planckian Censorship Conjecture (TCC) can be used to constrain the energy scale of inflation. The conclusions however depend on the assumptions about post-inflationary history of the Universe. E.g. in the standard case of a thermal post-inflationary history in which the Universe stays radiation dominated at all times from the end of inflation to the epoch of radiation matter equality, TCC has been used to argue that the Hubble parameter during inflation, $H_{\inf }$, is below $\mathcal{O}(0.1)\mathrm{GeV}$. Cosmological scenarios with a non-thermal post-inflationary history are well-motivated alternatives to the standard picture and it is interesting to find out the possible constraints which TCC imposes on such scenarios. In this work, we find out the amount of enhancement of the TCC compatible bound on $H_{\inf }$ if post-inflationary history before nucleosynthesis was non-thermal. We then argue that if TCC is correct, for a large class of scenarios, it is not possible for the Universe to have undergone a phase of moduli domination.

    ↳ astro-ph.COhep-phhep-thPRD(2019)·41 citations
48. 48*

    CMB anisotropy and BBN constraints on pre-recombination decay of dark matter to visible particles

    Sandeep Kumar Acharya🇮🇳 · Rishi Khatri🇮🇳

    Injection of high energy electromagnetic particles around the recombination epoch can modify the standard recombination history and therefore the CMB anisotropy power spectrum. Previous studies have put strong constraints on the amount of electromagnetic energy injection around the recombination era (redshifts $z\lesssim 4500$). However, energy injected in the form of energetic ($>$ keV) visible standard model particles is not deposited instantaneously. The considerable delay between the time of energy injection and the time when all energy is deposited to background baryonic gas and CMB photons, together with the extraordinary precision with which the CMB anisotropies have been measured, means that CMB anisotropies are sensitive to energy that was injected much before the epoch of recombination. We show that the CMB anisotropy power spectrum is sensitive to energy injection even at $z=10000$, giving stronger constraints compared to big bang nucleosynthesis and CMB spectral distortions. We derive, using Planck CMB data, the constraints on long-lived unstable particles decaying at redshifts $z\lesssim 10000$ (lifetime ${\tau }_X\gtrsim 10^{11}$s) by explicitly evolving the electromagnetic cascades in the expanding Universe, thus extending previous constraints to lower particle lifetimes. We also revisit the BBN constraints and show that the delayed injection of energy is important for BBN constraints. We find that the constraints can be weaker by a factor of few to almost an order of magnitude, depending on the energy, when we relax the quasi-static or on-the-spot assumptions.

    ↳ astro-ph.COastro-ph.HEhep-phJCAP(2019)·49 citations
49. 49*

    Shear viscosity in microscopic calculations of A+A collisions at energies of Nuclotron-based Ion Collider fAcility (NICA)

    M. Teslyk🇳🇴 · L. Bravina🇳🇴 · O. Panova🇳🇴 · O. Vitiuk🇳🇴 · E. Zabrodin🇳🇴

    Time evolution of shear viscosity $\eta$, entropy density $s$, and their ratio $\eta /s$ in the central area of central gold-gold collisions at NICA energy range is studied within the UrQMD transport model. The extracted values of energy density, net baryon density and net strangeness density are used as input to (i) statistical model of ideal hadron gas to define temperature, baryo-chemical potential and strangeness chemical potential, and to (ii) UrQMD box with periodic boundary conditions to study the relaxation process of highly excited matter. During the relaxation stage, the shear viscosity is determined in the framework of Green-Kubo approach. The procedure is performed for each of 20 time slices, corresponding to conditions in the central area of the fireball at times from 1~fm/$c$ to 20~fm/$c$. For all tested energies the ratio $\eta /s$ reaches minimum, ${\left(\eta /s\right)}_{min}\approx 0.3$ at $t\approx 5$~fm/$c$. Then it increases up to the late stages of the system evolution. This rise is accompanied by the drop of both, temperature and strangeness chemical potential, and increase of baryo-chemical potential.

    ↳ nucl-thhep-phnucl-exPRC(2020)·13 citations
50. 50*

    Flavored extended instanton in QCD

    Alexander Gorsky🇷🇺 · Andrey Grekov🇺🇸

    In this paper we discuss new flavored space-like defects in confined QCD which can be considered as the Euclidean extended instantons carrying the topologically quantized currents. We focus on the simplest 1d space-like defect - the S-Skyrmion solution extended in one space coordinate and localized in Euclidean time. It can be identified both in the holographic QCD and in the Chiral Perturbation Theory(ChPT). The Skyrmion charges get transformed into the corresponding currents for S-Skyrmion. The analogy with the Thouless pump and the quantum phase slip phenomena is mentioned.

    ↳ hep-thcond-mat.supr-conhep-lathep-phJHEP(2020)·2 citations
51. 51*

    Brane nucleation instabilities in non-AdS/non-CFT

    Oscar Henriksson🇫🇮 · Carlos Hoyos🇪🇸 · Niko Jokela🇫🇮

    We speculate that the weak gravity conjecture applied to theories with holographic duals bans the existence of disordered phases at zero temperature. We test this idea by introducing a non-zero baryon chemical potential in a deformation of the $SU(N_c)\times SU(N_c)$ Klebanov-Witten gauge theory with broken supersymmetry and conformal invariance. At low temperature, a disordered phase dual to a black brane geometry is unstable for low chemical potentials and metastable for high values. In the metastable phase, states with a partial Higgsing of the gauge group are favored over the normal disordered phase. This is reflected in the properties of the effective potential for color branes in the dual geometry, where the appearance of a global minimum outside the horizon signals the onset of a brane nucleation instability. When the Higgsing involves only one of the group factors, the global minimum remains at a finite distance from the horizon, making it possible to construct holographic duals to metastable "color superconducting" states. We also consider branes dual to excitations with baryon charge, but find that the extremal geometry remains marginally stable against the emission of particles carrying baryon charge independently of the strength of the deformation.

    ↳ hep-thhep-phJHEP(2020)·21 citations
52. 52*

    Resolving the Quenched $g_A$ Puzzle in Nuclei and Nuclear Matter

    Mannque Rho🇫🇷

    The long-standing puzzle of the quenched $g_A$ in nuclei -- and in dense matter -- is shown to have a simple resolution in a scale-symmetric HLS chiral Lagrangian at the Fermi-liquid fixed point. This resolution exposes scale-chiral symmetry, hidden in QCD in the vacuum, emerging in nuclear matter from low density to high compact-star density. It has important implications on "first principles" approaches to nuclear physics, such as the role of multi-body exchange currents in Gamow-Teller matrix elements in nuclei and in neutrinoless double $\beta$ decays for going Beyond the Standard Model.

    ↳ nucl-thhep-ph2 citations
53. 53*

    Warm brane inflation with an exponential potential: A consistent realization away from the swampland

    Vahid Kamali🇨🇦 · Meysam Motaharfar🇮🇷 · Rudnei O. Ramos🇧🇷

    It has very recently been realized that coupling branes to higher dimensional quantum gravity theories and considering the consistency of what lives on the branes, one is able to understand whether such theories can belong either to the swampland or to the landscape. In this regard, in the present work, we study a warm inflation model embedded in the Randall-Sundrum braneworld scenario. It is explicitly shown that this model belongs to the landscape by supporting a strong dissipative regime with an inflaton steep exponential potential. The presence of extra dimension effects from the braneworld allow achieving this strong dissipative regime, which is shown to be both theoretically and observationally consistent. In fact, such strong dissipation effects, which decrease towards the end of inflation, together with the extra dimension effect, allow the present realization to simultaneously satisfy all previous restrictions imposed on such a model and to evade the recently proposed swampland conjectures. The present implementation of this model, in terms of an exponential potential for the scalar field, makes it also a possible candidate for describing the late-time Universe in the context of a dissipative quintessential inflation model and we discuss this possibility in the Conclusions.

    ↳ gr-qcastro-ph.COhep-phhep-thPRD(2020)·64 citations
54. 54*

    Zero-point energies, dark matter, and dark energy

    Kevin Cahill🇺🇸

    A quantum field theory has finite zero-point energy if the sum over all boson modes $b$ of the $n$th power of the boson mass $m_b^n$ equals the sum over all fermion modes $f$ of the $n$th power of the fermion mass $m_f^n$ for $n=0$, 2, and 4. The zero-point energy of a theory that satisfies these three conditions with otherwise random masses is huge compared to the density of dark energy. But if in addition to satisfying these conditions, the sum of $m_b^4\log m_b/\mu$ over all boson modes $b$ equals the sum of $m_f^4\log m_f/\mu$ over all fermion modes $f$, then the zero-point energy of the theory is zero. The value of the mass parameter $\mu$ is irrelevant in view of the third condition ($n=4$). The particles of the standard model do not remotely obey any of these four conditions. But an inclusive theory that describes the particles of the standard model, the particles of dark matter, and all particles that have not yet been detected might satisfy all four conditions if pseudomasses are associated with the mean values in the vacuum of the divergences of the interactions of the inclusive model. Dark energy then would be the finite potential energy of the inclusive theory.

    ↳ physics.gen-phhep-ph1 citation

* 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.