Wed·Nov 18, 2020Wednesday·November 18, 2020

1. 01*

   Transasymptotics and hydrodynamization of the Fokker-Planck equation for gluons

   A. Behtash🇺🇸 · S. Kamata🇵🇱 · M. Martinez🇺🇸 · T. Schaefer🇺🇸 · V. Skokov🇺🇸

   We investigate the non-linear transport processes and hydrodynamization of a system of gluons undergoing longitudinal boost-invariant expansion. The dynamics is described within the framework of the Boltzmann equation in the small-angle approximation. The kinetic equations for a suitable set of moments of the one-particle distribution function are derived. By investigating the stability and asymptotic resurgent properties of this dynamical system, we demonstrate, that its solutions exhibit a rather different behavior for large (UV) and small (IR) effective Knudsen numbers. Close to the forward attractor in the IR regime the constitutive relations of each moment can be written as a multiparameter transseries. This resummation scheme allows us to extend the definition of a transport coefficient to the non-equilibrium regime naturally. Each transport coefficient is renormalized by the non-perturbative contributions of the non-hydrodynamic modes. The Knudsen number dependence of the transport coefficient is governed by the corresponding renormalization group flow equation. An interesting feature of the Yang-Mills plasma in this regime is that it exhibits transient non-Newtonian behavior while hydrodynamizing. In the UV regime the solution for the moments can be written as a power-law asymptotic series with a finite radius of convergence. We show that radius of convergence of the UV perturbative expansion grows linearly as a function of the shear viscosity to entropy density ratio. Finally, we compare the universal properties in the pullback and forward attracting regions to other kinetic models including the relaxation time approximation and the effective kinetic Arnold-Moore-Yaffe (AMY) theory.

   hep-phcond-mat.stat-mechhep-thnucl-th+1PRD(2021)·26 citations
2. 02*

   Chiral gauge leptoquark mass limits and branching ratios of $K_L^0,B^0,B_s\to l_i^{+}{l}_j^{-}$ decays with account of the general fermion mixing in leptoquark currents

   M. V. Martynov🇷🇺 · A. D. Smirnov🇷🇺

   The contributions of the chiral gauge leptoquarks $V^{L,R}$ induced by the chiral four color quark-lepton symmetry to the branching ratios of $K_L^0,B^0,B_s\to l_1{l}_2$ decays are calculated and analysed using the general parametrizations of the fermion mixing matrices in the leptoguark currents. From the current experimental data on these decays under assumption $m_{V^L}\ll m_{V^R}$ the lower mass limit $m_{V^L}\cos {\gamma }_L>5.68\text{mbox}TeV$ is found, which in particular case of equal gauge coupling constants gives $m_{V^L}>8.03\text{mbox}TeV$. The branching ratios of the decays under consideration predicted by the chiral gauge leptoquarks are calculated and analysed in dependence on the leptoquark masses and the mixing parameters. It is shown that in consistency with the current experimental data these branching ratios for $B_s,B^0\to \mu e$ decays can be close to their experimental limits and those for $B_s,B^0\to \tau e,\tau \mu$ decays can be of order of~$10^{-7}$. The calculated branching ratios will be useful in the further experimental searches for these decays.

   hep-phhep-exMod.Phys.Lett.A(2021)·6 citations
3. 03*

   IR-improved DGLAP parton shower effects for associated production of a W boson and jets in pp collisions at $\sqrt{s}=$8 and 13 TeV

   B. Shakerin🇺🇸 · B.F.L. Ward🇺🇸

   In a previous paper, hereafter referred to as I, we have analyzed the 7 TeV LHC data on W + jets events from the standpoint of IR-improved DGLAP parton shower effects, using the IR-improved Herwiri1.031 parton shower MC in comparison with the Herwig6.5 parton shower MC in the context of the exact $O({\alpha }_s)$ matrix element matched parton shower framework provided by MG5\_aMC@NLO. In the current paper, we extend this analysis to the LHC 8 and 13 TeV data to investigate the energy dependence of the results obtained in I. Specifically, W~+ jet events are generated in the MADGRAPH5\_aMC@NLO framework and showered by HERWIG6.521 and HERWIRI1.031 with $\mathtt{PTRMS}=2.2$ and 0 GeV, respectively. The differential cross sections are reported as functions of jet multiplicity, transverse linear momenta ($P_T$), the jet pesudo-rapidity ($\eta$) and the scalar sum of jet transverse momenta ($H_T$) for different jet multiplicities 1--3. The dijet cross sections as functions of transverse linear momenta, invariant mass of the dijet and the jet separation are shown as well. Distributions of angular correlations between the jets and the muon are examined as well and the corresponding cross sections are presented. The respective measured cross sections are compared with the exact next-to-leading-order (NLO) matrix element matched parton shower theoretical predictions provided by MADGRAPH5\_aMC@NLO/HERWIRI1.031~($\mathtt{PTRMS}=0)$ and MADGRAPH5\_aMC@NLO/HERWIG6.521~($\mathtt{PTRMS}=2.2\mathrm{GeV})$ and the phenomenological consequences are discussed with an eye toward their energy dependence.

   hep-phInt.J.Mod.Phys.A(2020)·2 citations
4. 04*

   Field dependence of the Yukawa coupling in the three flavor quark-meson model

   G. Fejos🇭🇺 · A. Patkos🇭🇺

   We investigate the renormalization group flow of the field-dependent Yukawa coupling in the framework of the three flavor quark-meson model. In a conventional perturbative calculation, given that the field rescaling is trivial, the Yukawa coupling does not get renormalized at the one-loop level if it is coupled to an equal number of scalar and pseudoscalar fields. Its field-dependent version, however, does flow with respect to the scale. Using the functional renormalization group technique, we show that it is highly nontrivial how to extract the actual flow of the Yukawa coupling as there are several new chirally invariant operators that get generated by quantum fluctuations in the effective action, which need to be distinguished from that of the Yukawa interaction.

   hep-phhep-thPRD(2021)·10 citations
5. 05*

   Neutrino amplitude decomposition in matter

   Hisakazu Minakata🇺🇸

   Observation of the interference between the atmospheric-scale and solar-scale oscillations is one of the challenging and tantalizing goals of the ongoing and upcoming neutrino experiments. An inevitable first step required for such analyses is to establish the way of how the oscillation $S$ matrix can be decomposed into the atmospheric and solar waves, the procedure dubbed as the amplitude decomposition. In this paper, with use of the perturbative framework proposed by Denton et al. (DMP), we establish the prescription for amplitude decomposition which covers the whole kinematical region of the terrestrial neutrino experiments. We analyze the limits to the atmospheric- and solar-resonance regions to argue that the dynamical two modes of the DMP decomposition can be interpreted as the matter-dressed atmospheric and solar oscillations. The expressions of the oscillation probability, which are decomposed into the non-interference and interference terms, are derived for all the relevant flavor oscillation channels. Through construction of the DMP decomposition, we reveal the nature of $\psi$ (${\theta }_{12}$ in matter) symmetry as due to the $S$ matrix rephasing invariance. A new picture of the DMP perturbation theory emerged, a unified perturbative framework for neutrino oscillation in earth matter.

   hep-phPRD(2021)·7 citations
6. 06*

   Mapping a new cluster of charmoniumlike structures at $e^{+}{e}^{-}$ collisions

   Jun-Zhang Wang🇨🇳 · Dian-Yong Chen🇨🇳 · Xiang Liu🇨🇳 · Takayuki Matsuki🇯🇵

   In this work, we find a Critical Energy induced Enhancement (CEE) mechanism for the general three-body open-charm process at the $e^{+}{e}^{-}$ collisions, which utilizes the peculiar kinematic behavior of the $e^{+}{e}^{-}$ annihilation process involving three-body final states. We present a general analysis of a three-body process $e^{+}{e}^{-}\to BC\to B(C\to DE)$. When the center-of-mass (CM) energy of the $e^{+}{e}^{-}$ collision satisfies a critical relation $\sqrt{s}=m_B+m_C$, there clearly exists the reflection peak of an intermediate $C$ state near the threshold of the invariant mass distribution of $m_{BE}$ or $m_{BD}$, whose formation is very sensitive to the CM energy. The reflection enhancement phenomenon induced at the critical energy means that a new cluster of charmoniumlike structures can be experimentally mapped. Taking an example of $e^{+}{e}^{-}\to D_s^{\ast -}{D}_{s2}^{\ast }(2573{)}^{+}\to D_s^{\ast -}(D^0{K}^{+})$, we further illustrate this novel phenomenon when $\sqrt{s}=4.680$ GeV. What is more important is that a series of optimal CM energy points to search for new charmoniumlike structures in three-body open-charm processes from $e^{+}{e}^{-}$ annihilation are suggested, which can be accessible at BESIII and further BelleII as a new research topic.

   hep-phPLB(2021)·16 citations
7. 07*

   Electric dipole moments of neutron and heavy quarks c, t in CP violating $U(1{)}_X$SSM

   Ben Yan🇨🇳 · Shu-Min Zhao🇨🇳 · Tai-Fu Feng🇨🇳

   We study and analyze the electric dipole moments (EDMs) of neutron and heavy quarks c, t in a CP-violating (CPV) supersymmetric U(1) extension of the standard model called $U(1{)}_X$SSM, whose local gauge group is $U(1{)}_X\times SU(3{)}_C\times SU(2{)}_L\times U(1{)}_Y$. The contributions from the one loop diagrams and the Weinberg operators are taken into account with the new introduced CPV phases beyond the minimum supersymmetric standard model(MSSM) being non-zero. Our numerical results show that in $U(1{)}_X$SSM the neutron EDM can be smaller than its experimental upper bound $1.8\times 10^{-26}$ e$\cdot$cm without a small CPV phase. The magnitudes of EDMs of heavy quarks c and t can reach $10^{-24}$ e$\cdot$cm. and $10^{-22}$ e$\cdot$cm respectively. This is favorable to the study of CPV.

   hep-phNPB(2022)·21 citations
8. 08*

   Transverse-momentum-dependent parton distribution functions up to twist 4 for spin-1 hadrons

   S. Kumano🇯🇵 · Qin-Tao Song🇨🇳

   We show possible transverse-momentum-dependent parton distribution functions (TMDs) for spin-1 hadrons including twist-3 and 4 functions in addition to the leading twist-2 ones by investigating all the possible decomposition of a quark correlation function in the Lorentz-invariant way. The Hermiticity and parity invariance are imposed in the decomposition; however, the time-reversal invariance is not used due to an active role of gauge links in the TMDs. Therefore, there exist time-reversal-odd functions in addition to the time-reversal even ones in the TMDs. We list all the functions up to twist-4 level because there were missing terms associated with the lightcone vector $n$ in previous works on the twist-2 part and there was no correlation-function study in the twist-3 and 4 parts for spin-1 hadrons. We show that 40 TMDs exist in the tensor-polarized spin-1 hadron in twists 2, 3, and 4. Some expressions of twist-2 structure functions are modified from previous derivations due to the new terms with $n$, and we find 30 new structure functions in twists 3 and 4 in this work. Since time-reversal-odd terms of the collinear correlation function should vanish after integrals over the partonic transverse momentum, we obtain new sum rules for the time-reversal-odd structure functions, $\int d^2{k}_T{h}_{LT}=\int d^2{k}_T{h}_{LL}=\int d^2{k}_T{h}_{3LL}=0$. In addition, we indicate that new transverse-momentum-dependent fragmentation functions exist in tensor-polarized spin-1 hadrons. The TMDs are rare observables to find explicit color degrees of freedom in terms of color flow, which cannot be usually measured because the color is confined in hadrons.

   hep-phhep-exhep-latnucl-thPRD(2021)·39 citations
9. 09*

   Toward charged $Z_{cs}(3985)$ structure under a reflection mechanism

   Jun-Zhang Wang🇨🇳 · Qin-Song Zhou🇨🇳 · Xiang Liu🇨🇳 · Takayuki Matsuki🇯🇵

   Very recently, the BESIII collaboration reported a charged hidden-charm structure with strangeness in the recoil mass of $K^{+}$ of a process $e^{+}{e}^{-}\to D_s^{\ast -}{D}^0{K}^{+}$ or $D_s^{-}{D}^{\ast 0}{K}^{+}$, which is named as $Z_{cs}(3985{)}^{-}$. The newly observed charged structure can be treated as a partner structure with strangeness of well-known $Z_c(3885{)}^{-}$ reported in a process $e^{+}{e}^{-}\to D^{\ast -}{D}^0{\pi }^{+}$. In this work, we propose a novel picture to understand the nature of $Z_{cs}(3985)$. By performing a combined analysis for the line shape of the recoil mass distribution of $K^{+}$ at five energy points $\sqrt{s}=4.628,4.641,4.661,4.681,4.698$ GeV, we find that the $Z_{cs}(3985)$ can be explained as a reflection structure of charmed-strange meson $D_{s2}^{\ast }(2573)$, which is produced from the open-charm decay of $Y(4660)$ with a $D_s^{\ast }$ meson. Furthermore, we predicted the angular distribution of final state $D_s^{\ast -}$ in process $e^{+}{e}^{-}\to D_s^{\ast -}{D}^0{K}^{+}$ based on our proposed reaction mechanism, which may be an essential criterion to test the non-resonant nature of $Z_{cs}(3985)$ further.

   hep-phhep-exEPJC(2021)·47 citations
10. 10*

    $Z_{cs}(3985{)}^{-}$ as the $U$-spin partner of $Z_c(3900{)}^{-}$ and implication of other states in the ${\text{SU(3)}}_F$ symmetry and heavy quark symmetry

    Lu Meng🇩🇪 · Bo Wang🇨🇳 · Shi-Lin Zhu🇨🇳

    Recently, for the first time, the BESIII Collaboration reported the strange hidden charm tetraquark states $Z_{cs}(3985{)}^{-}$ in the $K^{+}$ recoil-mass spectrum near the $D_s^{-}{D}^{\ast 0}/D_s^{\ast -}{D}^0$ mass thresholds in the processes of $e^{+}{e}^{-}\to K^{+}(D_s^{-}{D}^{\ast 0}+D_s^{\ast -}{D}^0)$ at $\sqrt{s}=4.681$ GeV. The significance was estimated to be 5.3 $\sigma$. We show that the newly observed $Z_{cs}(3985{)}^{-}$ state is the $U$-spin partner of $Z_c(3900{)}^{-}$ as a resonance within coupled-channel calculation in the ${\text{SU(3)}}_F$ symmetry and heavy quark spin symmetry (HQSS). In the ${\text{SU(3)}}_F$ symmetry, we introduce the $G_{U/V}$ parity to construct the flavor wave functions of the $Z_{cs}$ states. In a unified framework, we consider the $J/\psi \pi (K)$, ${\bar{D}}_{(s)}{D}^{\ast }/{\bar{D}}_{(s)}^{\ast }D$ coupled-channel effect with the contact interaction. With the masses and widths of $Z_c(3900)$ and $Z_c(4020)$, we determine all the unknown coupling constants. We obtain mass and width of $Z_{cs}(3985)$ in good agreement with the experimental results, which strongly supports the $Z_{cs}$ states as the $U/V$-spin partner states of the charged $Z_c(3900)$. We also calculate the ratio of the partial decay widths of $Z_{cs}(3985)$, which implies that the ${\bar{D}}_s{D}^{\ast }/{\bar{D}}_s^{\ast }D$ decay modes are dominant. We also predict the $Z_{cs}^{\prime }$ states with a mass around $4130$ MeV and width around $30$ MeV, which are the $U/V$-spin partner states of the charged $Z_c(4020)$ and HQSS partner states of the $Z_{cs}(3985)$. In the hidden bottom sector, we predict the strange tetraquark states $Z_{bs}$ and $Z_{bs}^{\prime }$ with a mass around 10700 MeV and 10750 MeV, which are the $U/V$-spin partner states of $Z_b(10610{)}^{\pm }$ and $Z_b(10650{)}^{\pm }$, respectively.

    hep-phhep-exhep-latnucl-thPRD(2020)·81 citations
11. 11*

    Can $Z_{cs}(3985)$ be a molecular state of ${\bar{D}}_s^{\ast }D$ and ${\bar{D}}_s{D}^{\ast }$ ?

    Ming-Zhu Liu🇨🇳 · Jun-Xu Lu🇨🇳 · Tian-Wei Wu🇨🇳 · Ju-Jun Xie🇨🇳 · Li-Sheng Geng🇨🇳

    We study the $Z_{cs}(3985)$ state recently observed by the BESIII Collaboration in the one-boson-exchange model, assuming that it is a ${\bar{D}}_s^{(\ast )}{D}^{(\ast )}$ molecule, which has the quark content $c\bar{c}s\bar{q}$ with $q=u$, $d$. It is shown that the one-boson-exchange potential is too weak to generate dynamcally ${\bar{D}}_{s}D$, ${\bar{D}}_s^{\ast }D$, and ${\bar{D}}_s{D}^{\ast }$ states, while for the case of ${\bar{D}}_s^{\ast }{D}^{\ast }$, very loosely bound states are likely, with binding energies of the order of several MeV. We conclude that, the observed $Z_{cs}(3985)$ state, if confirmed by further experiments, cannot be a pure hadronic molecular state of ${\bar{D}}_s{D}^{\ast }$ and ${\bar{D}}_s^{\ast }D$ and could consist of large components of compact nature.

    hep-ph22 citations
12. 12*

    Strange molecular partners of the $Z_c(3900)$ and $Z_c(4020)$

    Zhi Yang🇨🇳 · Xu Cao🇨🇳 · Feng-Kun Guo🇨🇳 · Juan Nieves🇪🇸 · Manuel Pavon Valderrama🇨🇳

    Quantum Chromodynamics presents a series of exact and approximate symmetries which can be exploited to predict new hadrons from previously known ones. The $Z_c(3900)$ and $Z_c(4020)$ resonances, which have been theorized to be isovector $D^{\ast }\bar{D}$ and $D^{\ast }{\bar{D}}^{\ast }$ molecules [$I^G(J^{PC})=1^{-}(1^{+-})$], are no exception. Here we argue that from SU(3)-flavor symmetry, we should expect the existence of strange partners of the $Z_c$'s with hadronic molecular configurations $D^{\ast }{\bar{D}}_s$-$D{\bar{D}}_s^{\ast }$ and $D^{\ast }{\bar{D}}_s^{\ast }$ (or, equivalently, quark content $c\bar{c}s\bar{q}$, with $q=u,d$). The quantum numbers of these $Z_{cs}$ and $Z_{cs}^{\ast }$ resonances would be $I(J^P)$ = $\frac{1}{2}(1^{+})$. The predicted masses of these partners depend on the details of the theoretical scheme used, but they should be around the $D^{\ast }{\bar{D}}_s$-$D{\bar{D}}_s^{\ast }$ and $D^{\ast }{\bar{D}}_s^{\ast }$ thresholds, respectively. Moreover, any of these states could be either a virtual pole or a resonance. We show that, together with a possible triangle singularity contribution, such a picture nicely agrees with the very recent BESIII data of the $e^{+}{e}^{-}\to K^{+}(D_s^{-}{D}^{\ast 0}+D_s^{\ast -}{D}^0)$.

    hep-phhep-exhep-latnucl-thPRD(2021)·101 citations
13. 13*

    About the exotic structure of $Z_{cs}$

    Bing-Dong Wan🇨🇳 · Cong-Feng Qiao🇨🇳

    Very recently a new hadronic structure around $3.98$ GeV was observed in BESIII experiment. From its decay modes, it is reasonable for people to assign it to the category of exotic state, say $Z_{cs}^{+}$, the stranged-parter of $Z_c(3900)$. This finding indicates for the first time the exotic state with strange quark in charm sector, and hence has a peculiar importance. By virtue of the QCD Sum Rule technique, we analyze the $Z_{cs}^{+}$ about its possible configuration and physical properties, and find it could be configured as a mixture of two types of structures, $[1_c{]}_{\bar{c}u}\otimes [1_c{]}_{\bar{s}c}$ and $[1_c{]}_{\bar{c}c}\otimes [1_c{]}_{\bar{s}u}$, or $[3_c{]}_{\bar{c}u}\otimes [{\bar{3}}_c{]}_{\bar{s}c}$ and $[3_c{]}_{\bar{c}c}\otimes [{\bar{3}}_c{]}_{\bar{s}u}$, with $J^P=1^{+}$. Physically, it then appears to be the emergence of a compound of four possible currents in each configuration, which tells the single current evaluation of hadron spectroscopy and their decay properties are sometimes not enough. We find in both cases the energy spectra may fit well with the experimental observation, i.e. $3.98$ GeV, within the uncertainties, while noted the former is not favored by vector meson exchange model. Various $Z_{cs}^{+}(3980)$ decay modes are evaluated, which are critical for pinning down its configuration and left for experimental verification. We also predict the mass of $Z_{cs}^0$, the neutral partner of $Z_{cs}^{+}(3980)$, and analyze its dominant decay probabilities.

    hep-phNPB(2021)·84 citations
14. 14*

    Dark Holograms and Gravitational Waves

    Francesco Bigazzi🇮🇹 · Alessio Caddeo🇮🇹 · Aldo L. Cotrone🇮🇹 · Angel Paredes🇪🇸

    Spectra of stochastic gravitational waves (GW) generated in cosmological first-order phase transitions are computed within strongly correlated theories with a dual holographic description. The theories are mostly used as models of dark sectors. In particular, we consider the so-called Witten-Sakai-Sugimoto model, a $SU(N)$ gauge theory coupled to different matter fields in both the fundamental and the adjoint representations. The model has a well-known top-down holographic dual description which allows us to perform reliable calculations in the strongly coupled regime. We consider the GW spectra from bubble collisions and sound waves arising from two different kinds of first-order phase transitions: a confinement/deconfinement one and a chiral symmetry breaking/restoration one. Depending on the model parameters, we find that the GW spectra may fall within the sensibility region of ground-based and space-based interferometers, as well as of Pulsar Timing Arrays. In the latter case, the signal could be compatible with the recent potential observation by NANOGrav. When the two phase transitions happen at different critical temperatures, characteristic spectra with double frequency peaks show up. Moreover, in this case we explicitly show how to correct the redshift factors appearing in the formulae for the GW power spectra to account for the fact that adiabatic expansion from the first transition to the present times cannot be assumed anymore.

    hep-phastro-ph.COhep-thJHEP(2021)·72 citations
15. 15*

    Study $B_{(s)}^0$ decays into $\varphi$ and a scalar or vector meson

    Hiwa A. Ahmed🇨🇳 · Zhong-Yu Wang🇨🇳 · Zhi-Feng Sun🇨🇳 · C. W. Xiao🇨🇳

    In the present work, we investigate the decays of $B_s^0\to \varphi {\pi }^{+}{\pi }^{-}$ and $B^0\to \varphi {\pi }^{+}{\pi }^{-}$ with the final state interactions based on the chiral unitary approach. In the final state interactions of the ${\pi }^{+}{\pi }^{-}$ with its coupled channels, we study the effects of the $\eta \eta$ channel in the two-body interactions for the reproduction of the $f_0(980)$ state. Our results for the ${\pi }^{+}{\pi }^{-}$ invariant mass distributions of the decay $B_s^0\to \varphi {\pi }^{+}{\pi }^{-}$ describe the experimental data up to 1 GeV well, with the resonance contributions from the $f_0(980)$ and $\rho$. For the predicted invariant mass distributions of the $B^0\to \varphi {\pi }^{+}{\pi }^{-}$ decay, we found that the contributions from the $f_0(500)$ are significant except for the ones from the $f_0(980)$ state. With some experimental branching ratios as input to determine the production vertex factors, we make some predictions for the branching ratios of the other final decay channels, including the vector mesons, in the $B_{(s)}^0$ decays, where some of them are consistent with the experimental ones within the uncertainties.

    hep-phEPJC(2021)·16 citations
16. 16*

    Tsallis statistics, fractals and QCD

    Airton Deppman🇧🇷 · Eugenio Megias🇪🇸 · Debora P. Menezes🇧🇷

    We study the non-extensive Tsallis statistics and its applications to QCD and high energy physics, and analyze the possible connections of this statistics with a fractal structure of hadrons. Then, we describe how scaling properties of Yang-Mills theories allow the appearance of self-similar structures in gauge fields, which actually behave as fractals. The Tsallis entropic index, $q$, is deduced in terms of the field theory parameters, resulting in a good agreement with the value obtained experimentally.

    hep-phhep-thnucl-thNucl.Part.Phys.Proc.(2021)·4 citations
17. 17*

    A varying Dark Energy effective speed of sound parameter in the phantom Universe

    Imanol Albarran🇵🇹 · Mariam Bouhmadi-López🇪🇸 · João Marto🇵🇹

    We analyse the phenomenological effects of a varying Dark Energy (DE) effective speed of sound parameter, $c_{\text{sd}}^2$, on the cosmological perturbations of three phantom DE models. Each of these models induce a particular abrupt future event known as Big Rip (BR), Little Rip (LR), and Little Sibling of the Big Rip (LSBR). In this class of abrupt events, all the bound structures in the Universe would be ripped apart at a finite cosmic time. We compute the evolution of the perturbations, $f{\sigma }_8$ growth rate and forecast the current matter power spectrum. We vary the $c_{\text{sd}}^2$ parameter in the interval $[0,1]$ and compute the relative deviation with respect $c_{\text{sd}}^2=1$. In addition, we analyse the effect of gravitational potential sign flip that occurs at very large scale factors as compared with the current one.

    ↳ gr-qcastro-ph.COhep-phEPJC(2021)·6 citations
18. 18*

    Impact of ATLAS $V$ + jets data on PDF fits

    Francesco Giuli🇮🇹

    This proceeding presents a new set of proton parton distribution functions, ATLASepWZVjet20, produced in an analysis at next-to-next-to-leading-order in QCD. The new datasets considered are the ATLAS measurements of $W^{\pm }$ and $Z$ boson production in association with jets in $pp$ collisions at $\sqrt{s}$ = 8 TeV at the LHC with integrated luminosities of 20.2 fb${}^{-1}$ and 19.9 fb${}^{-1}$ respectively. The analysis also considers the ATLAS measurements of differential $W^{\pm }$ and $Z$ boson production at $\sqrt{s}$ = 7 TeV with an integrated luminosity of 4.6 fb${}^{-1}$ and deep-inelastic scattering data from $e^{\pm }p$ collisions at the HERA accelerator. An improved determination of the sea-quark densities at high Bjorken $x$ is shown, while confirming a strange-quark density of similar size as the up-and down-sea quark densities in the range $x\sim$ 0.02 found by previous ATLAS analyses.

    ↳ hep-exhep-phNucl.Part.Phys.Proc.(2021)·4 citations
19. 19*

    Superradiance Exclusions in the Landscape of Type IIB String Theory

    Viraf M. Mehta🇩🇪 · Mehmet Demirtas🇺🇸 · Cody Long🇺🇸 · David J. E. Marsh🇩🇪 · Liam McAllister🇺🇸 · Matthew J. Stott🇬🇧

    We obtain constraints from black hole superradiance in an ensemble of compactifications of type IIB string theory. The constraints require knowing only the axion masses and self-interactions, and are insensitive to the cosmological model. We study more than $2\cdot 10^5$ Calabi-Yau manifolds with Hodge numbers $1\le h^{1,1}\le 491$ and compute the axion spectrum at two reference points in moduli space for each geometry. Our computation of the classical theory is explicit, while for the instanton-generated axion potential we use a conservative model. The measured properties of astrophysical black holes exclude parts of our dataset. At the point in moduli space corresponding to the tip of the stretched Kähler cone, we exclude $\approx 50\%$ of manifolds in our sample at 95% C.L., while further inside the Kähler cone, at an extremal point for realising the Standard Model, we exclude a maximum of $\approx 7\%$ of manifolds at $h^{1,1}=11$, falling to nearly zero by $h^{1,1}=100$.

    ↳ hep-thhep-ph110 citations
20. 20*

    Topological Stars and Black Holes

    Ibrahima Bah🇺🇸 · Pierre Heidmann🇺🇸

    We study smooth bubble spacetimes in five-dimensional Einstein-Maxwell theory that resemble four-dimensional magnetic black holes upon Kaluza-Klein reduction. We denote them as Topological Stars since they have topological cycles supported by magnetic flux. They can be macroscopically large compared to the size of the Kaluza-Klein circle and could describe qualitative properties of microstate geometries for astrophysical black holes. We also describe five-dimensional black strings without curvature singularity, the interior caps as a two-dimensional Milne space with a bubble.

    ↳ hep-thgr-qchep-phPRL(2021)·75 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.