Mon·Sep 6, 2021Monday·September 6, 2021

1. 01*

   Charmed Baryon Physics Circa 2021

   Hai-Yang Cheng🇹🇼

   This is an update of the two articles (H.Y. Cheng, 2009; Cheng, 2015) in which charmed baryon physics around 2007 and 2015, respectively, were reviewed. In this review we emphasize the experimental progress and the theoretical development since 2015.

   hep-phhep-exChin.J.Phys.(2022)·132 citations
2. 02*

   Probing double hadron resonances by the complex scaling method

   Zhuo Yu🇨🇳 · Mao Song🇨🇳 · Jian-You Guo🇨🇳 · Yu Zhang🇨🇳 · Gang Li🇨🇳

   Many newly discovered excited states are interpreted as bound states of hadrons. Can these hadrons also form resonant states? In this paper, we extend the complex scaling method (CSM) to calculate the bound state and resonant state consistently for the ${\Lambda }_{c}D(\bar{D})$ and ${\Lambda }_c{\Lambda }_c({\bar{\Lambda }}_c)$ systems. For these systems, the $\pi ,\eta ,\rho$ meson exchange contributions are suppressed, the contributions of intermediate- and short-range forces from $\sigma /\omega$ exchange are dominant. Our results indicate that ${\Lambda }_{c}D$ system can not form bound state and resonant state. There exist resonant states in a wide range of parameters for ${\Lambda }_c\bar{D}$ and ${\Lambda }_c{\Lambda }_c({\bar{\Lambda }}_c)$ systems. For these systems, the larger bound state energy, the easier to form resonant states. Among all the resonant states, the energies and widths of the P wave resonant states are smaller and more stable, which is possible to be observed in the experiments. The energies of D and F wave resonant states can reach dozens of MeV and the widths can reach hundreds of MeV.

   hep-phPRC(2021)·12 citations
3. 03*

   On long-lived electroweak-singlet coloured scalars

   Christian T Preuss🇦🇺 · German Valencia🇦🇺

   There has been much recent interest in long-lived massive particles at the LHC, understood as those with lifetimes between tens of micrometers and several meters. In this context we consider the possibility of long-lived electroweak singlet scalars charged under colour $\mathrm{SU}(3)$ with masses near a TeV. The shortest lifetime of interest is already longer than typical hadronisation scales. These exotic new particles would therefore appear as colour singlet bound states of the new scalars with quarks and gluons and it is their colour charge that prevents them from decaying. In particular we consider colour representations consistent with maintaining asymptotic freedom, those with dimensionality $d_R\le 15$. We find that only the octets can decay, and they do so into multi-jet final states through the two-gluon channel. The other representations are stable and form fractionally charged colour singlets, with the decuplet being the only one that can form electrically neutral colour singlets.

   hep-phPRD(2021)·6 citations
4. 04*

   Searching for heavy leptoquarks at a muon collider

   Sitian Qian🇨🇳 · Congqiao Li🇨🇳 · Qiang Li🇨🇳 · Fanqiang Meng🇨🇳 · Jie Xiao🇨🇳 · Tianyi Yang🇨🇳 · Meng Lu🇨🇳 · Zhengyun You🇨🇳

   The LHCb Collaboration recently gave an update on testing lepton flavour universality with $B^{+}\to K^{+}{\ell }^{+}{\ell }^{-}$, in which a 3.1 standard deviations from the standard model prediction was observed. The g-2 experiment also reports a 3.3 standard deviations from the standard model on muon anomalous magnetic moment measurement. These deviations could be explained by introducing new particles including leptoquarks. In this paper, we show the possibility to search for heavy spin-1 leptoquarks at a future TeV scale muon collider by performing studies from three channels: 1) same flavour final states with either two bottom or two light quarks, 2) different flavour quark final states, and 3) a so-called "VXS" process representing the scattering between a vector boson and a leptoquark to probe the coupling between leptoquark and tau lepton. We conclude that a 3 TeV muon collider with $3a{b}^{-1}$ of integrated luminosity is already sufficient to cover the leptoquark parameter space in order to explain the LHCb lepton flavour universality anomaly.

   hep-phJHEP(2021)·38 citations
5. 05*

   Effective Debye Screening Mass in an Anisotropic Quark Gluon Plasma

   Lihua Dong🇨🇳 · Yun Guo🇨🇳 · Ajaharul Islam🇺🇸 · Michael Strickland🇺🇸

   Due to the rapid longitudinal expansion of the quark-gluon plasma created in heavy-ion collisions, large local-rest-frame momentum-space anisotropies are generated during the system's evolution. These momentum-space anisotropies complicate the modeling of heavy-quarkonium dynamics in the quark-gluon plasma due to the fact that the resulting inter-quark potentials are spatially anisotropic, requiring real-time solution of the 3D Schrödinger equation. Herein, we introduce a method for reducing anisotropic heavy-quark potentials to isotropic ones by introducing an effective screening mass that depends on the quantum numbers $l$ and $m$ of a given state. We demonstrate that, using the resulting effective Debye screening masses, one can solve a 1D Schrödinger equation and reproduce the full 3D results for the energies and binding energies of low-lying heavy-quarkonium bound states to relatively high accuracy. The resulting effective isotropic potential models could provide an efficient method for including momentum-anisotropy effects in open quantum system simulations of heavy-quarkonium dynamics in the quark-gluon plasma.

   hep-phnucl-thPRD(2021)·12 citations
6. 06*

   Studying Both the Universe and Neutrinos Themselves Using Cosmic and Astrophysical Neutrinos

   Saul Hurwitz🇯🇵

   With neutrino astronomy just beginning to burgeon, and the prospects of detecting the cosmic neutrino background closer than ever, we live in an era with the unique opportunity not only to investigate the universe with this novel probe, but conversely to utilise the cosmos as a laboratory to study neutrinos themselves. This thesis aims to expound on some of the ways to seize this opportunity, using corollaries of our standard model, gravitational lensing, inverse beta decay, and the neutrino's spin to achieve our goals. Theoretically, these tools prove insightful and impressive, but difficulties in experimental precision and a low rate of certain astrophysical events hinder the capabilities of these mechanisms. Regardless, the future of neutrino astronomy is certainly bright.

   hep-phhep-ex0 citations
7. 07*

   Revisit the isospin violating decays of $X(3872)$

   Lu Meng🇩🇪 · Guang-Juan Wang🇯🇵 · Bo Wang🇨🇳 · Shi-Lin Zhu🇨🇳

   In this work, we revisit the isospin violating decays of $X(3872)$ in a coupled-channel effective field theory. In the molecular scheme, the $X(3872)$ is interpreted as the bound state of ${\bar{D}}^{\ast 0}{D}^0/{\bar{D}}^0{D}^{\ast 0}$ and $D^{\ast -}{D}^{+}/D^{-}{D}^{\ast +}$ channels. In a cutoff-independent formalism, we relate the coupling constants of $X(3872)$ with the two channels to the molecular wave function. The isospin violating decays of $X(3872)$ are obtained by two equivalent approaches, which amend some deficiencies about this issue in literature. In the quantum field theory approach, the isospin violating decays arise from the coupling constants of $X(3872)$ to two di-meson channels. In the quantum mechanics approach, the isospin violating is attributed to wave functions at the origin. We illustrate that how to cure the insufficient results in literature. Within the comprehensive analysis, we bridge the isospin violating decays of $X(3872)$ to its inner structure. Our results show that the proportion of the neutral channel in $X(3872)$ is over $80\%$. As a by-product, we calculate the strong decay width of $X(3872)\to {\bar{D}}^0{D}^0{\pi }^0$ and radiative one $X(3872)\to {\bar{D}}^0{D}^0\gamma$. The strong decay width and radiative decay width are about 30 keV and 10 keV, respectively, for the binding energy from $-300$ keV to $-50$ keV.

   hep-phhep-exhep-latnucl-thPRD(2021)·36 citations
8. 08*

   Selecting the physical solution via $\eta$-${\eta }^{\prime }$ mixing

   Kai Zhu🇨🇳

   Based on $\eta$-${\eta }^{\prime }$ mixing analysis, we propose a novel method to extract the physical solutions for the hadronic properties of the $Y(4230)$ resonance from the experimental data. Experimentally, multiple solutions have been reported in the decays of $Y(4230)\to \eta J/\psi$ and $Y(4230)\to {\eta }^{\prime }J/\psi$. Utilizing our method, we determine a unique solution for the process $Y(4230)\to {\eta }^{\prime }J/\psi$. Likewise, two solutions for the process $Y(4230)\to \eta J/\psi$ are preferred among the originally reported three solutions under the assumption that $Y(4230)$ dose not take an $s\bar{s}$ component.

   hep-phhep-exPRD(2022)·5 citations
9. 09*

   The QCD Equation of State in Small Systems

   W. A. Horowitz🇿🇦 · Alexander Rothkopf🇳🇴

   We present first results on finite system size corrections to the equation of state, trace anomaly, and speed of sound for two model systems: 1) free, massless scalar theory and 2) quenched QCD with periodic boundary conditions (PBC). We further present work-in-progress results for quenched QCD with Dirichlet boundary conditions.

   hep-phhep-latnucl-thSciPost Phys.Proc.(2022)·12 citations
10. 10*

    First indication on self-similarity of strangeness production in $Au+Au$ collisions at RHIC: Search for signature of phase transition in nuclear matter

    M.V. Tokarev (1,2)🇷🇺 · I.Zborovsky (3) ( (1) Veksler and Baldin Laboratory of High Energy Physics, Joint Institute for Nuclear Research, Dubna, Russia (2) Dubna State University, Dubna, Russia (3) The Czech Academy of Science, Nuclear Physics Institute, Czech Republic, Rez, Czech Republic )🇨🇿

    New results of analysis of $K_S^0-$meson spectra measured over a wide range of energy $\sqrt{s_{NN}}=7.7-200$ GeV and centrality in $Au+Au$ collisions by the STAR Collaboration at RHIC using the $z$-scaling approach are presented. Indication on self-similarity of fractal structure of nuclei and fragmentation processes with $K_S^0$ probe is demonstrated. The energy loss as a function of the collision energy, centrality and transverse momentum of the inclusive strange meson is estimated.

    hep-phSciPost Phys.Proc.(2022)·1 citation
11. 11*

    Electroweak Skyrmions in the HEFT

    Juan Carlos Criado🇬🇧 · Valentin V. Khoze🇬🇧 · Michael Spannowsky🇬🇧

    We study the existence of skyrmions in the presence of all the electroweak degrees of freedom, including a dynamical Higgs boson, with the electroweak symmetry being non-linearly realized in the scalar sector. For this, we use the formulation of the Higgs Effective Field Theory (HEFT). In contrast with the linear realization, a well-defined winding number exists in HEFT for all scalar field configurations. We classify the effective operators that can potentially stabilize the skyrmions and numerically find the region in parameter spaces that support them. We do so by minimizing the static energy functional using neural networks. This method allows us to obtain the minimal-energy path connecting the vacuum to the skyrmion configuration and calculate its mass and radius. Since skyrmions are not expected to be produced at colliders, we explore the experimental and theoretical bounds on the operators that generate them. Finally, we briefly consider the possibility of skyrmions being dark matter candidates.

    hep-phhep-thJHEP(2021)·4 citations
12. 12*

    Quark and scalar propagators at next-to-eikonal accuracy in the CGC through a dynamical background gluon field

    Tolga Altinoluk🇵🇱 · Guillaume Beuf🇵🇱

    We revisit the calculation of quark and scalar propagators in a gluon background field at Next-to-Eikonal accuracy, which will provide the first power correction to scattering processes in the high-energy limit, including gluon saturation effects. The two main results of our study are as follows. First, we derive a very general Next-to-Eikonal expansion of the quark propagator in terms of the scalar propagator, which allows us to isolate spinor-specific Next-to-Eikonal corrections from the universal ones. Second, we present a new method allowing, for the first time, a systematic calculation of the Next-to-Eikonal corrections coming from the $x^{-}$ dependence of the background field. This opens the possibility to study high-energy scattering processes on a target with non-trivial dynamics instead of on a static one, by going beyond infinite Lorentz time dilation of the target.

    hep-phPRD(2022)·60 citations
13. 13*

    Global CP asymmetries in charmless three-body $B$ decays with final state interactions

    Ignacio Bediaga🇧🇷 · Tobias Frederico🇧🇷 · Patricia C. Magalhaes🇧🇷 · Diego Torres Machado🇧🇷

    We propose a theoretical framework to understand the observable charge-parity (CP) violation in charmless three-body $B^{\pm }$ decays. The decay amplitudes put together the $\pi \pi \to KK$ re-scattering and the U-spin symmetry, treated within a CPT invariant framework. This approach applied to a two-channel model provides the magnitudes and signs of the ratios of the global CP asymmetries for $B^{\pm }\to K^{\pm }{\pi }^{+}{\pi }^{-}$, $B^{\pm }\to K^{\pm }{K}^{+}{K}^{-}$, $B^{\pm }\to {\pi }^{\pm }{K}^{+}{K}^{-}$ and $B^{\pm }\to {\pi }^{\pm }{\pi }^{+}{\pi }^{-}$ decays, compatible with those obtained from the available experimental data. In addition, by considering the neutral channels we predict the ratios for the global CP asymmetries for these decays.

    hep-phhep-exPLB(2022)·8 citations
14. 14*

    Do Minimal Parity Solutions to the Strong CP Problem Work?

    Jordy de Vries🇳🇱 · Patrick Draper🇺🇸 · Hiren H. Patel🇺🇸

    One class of solutions to the strong CP problem relies on generalized parity symmetries. A minimal model of this type, constructed by Babu and Mohapatra and based on a softly broken parity symmetry, has the remarkable property that effective QCD vacuum angle $\bar{\theta }$ vanishes up to one-loop order. We compute the leading two-loop contributions to $\bar{\theta }$ in this model and estimate subleading contributions. In contrast to previous estimates, we argue that $\bar{\theta }$ is not suppressed by the weak scale, and we find contributions of order $10^{-3}$-$10^{-2}$ multiplying unknown mixing angles and phases. Thus the model does not generically address the strong CP problem, but it might be made consistent with $\bar{\theta }<10^{-10}$ in some corners of parameter space. For such non-generic parameters, $\bar{\theta }$ is still likely to be just below present bounds, and therefore provides the dominant source of hadronic EDMs. We discuss the resulting EDM phenomenology.

    hep-phnucl-th39 citations
15. 15*

    Gauge-field production during axion inflation in the gradient expansion formalism

    E.V. Gorbar🇺🇦 · K. Schmitz🇨🇭 · O.O. Sobol🇨🇭 · S.I. Vilchinskii🇨🇭

    We study the explosive production of gauge fields during axion inflation in a novel gradient expansion formalism that describes the time evolution of a set of bilinear electromagnetic functions in position space. Based on this formalism, we are able to simultaneously account for two important effects that have thus far been mostly treated in isolation: (i) the backreaction of the produced gauge fields on the evolution of the inflaton field and (ii) the Schwinger pair production of charged particles in the strong gauge-field background. This allows us to show that the suppression of the gauge-field production due to the Schwinger effect can prevent the backreaction in scenarios in which it would otherwise be relevant. Moreover, we point out that the induced current, $\mathbf{J}=\sigma \mathbf{E}$, also dampens the Bunch-Davies vacuum fluctuations deep inside the Hubble horizon. We describe this suppression by a new parameter $\Delta$ that is related to the time integral over the conductivity $\sigma$ which hence renders the description of the entire system inherently nonlocal in time. Finally, we demonstrate how our formalism can be used to construct highly accurate solutions for the mode functions of the gauge field in Fourier space, which serves as a starting point for a wealth of further phenomenological applications, including the phenomenology of primordial perturbations and baryogenesis.

    hep-phastro-ph.COhep-thPRD(2021)·99 citations
16. 16*

    Vacuum Stability Conditions and Potential Minima for a Matrix Representation in Lightcone Orbit Space

    Kristjan Kannike🇪🇪

    The orbit space for a scalar field in a complex square matrix representation obtains a Minkowski space structure from the Cauchy-Schwarz inequality. It can be used to find vacuum stability conditions and minima of the scalar potential. The method is suitable for fields such as a bidoublet, an $SU(2)$ triplet or $SU(3)$ octet. We use the formalism to find the vacuum stability conditions for the left-right symmetric potential of a bidoublet and left and right Higgs doublets.

    hep-phEPJC(2021)·10 citations
17. 17*

    Interplay of dineutrino modes with semileptonic rare $\mathbf{B}$-decays

    Rigo Bause🇩🇪 · Hector Gisbert🇩🇪 · Marcel Golz🇩🇪 · Gudrun Hiller🇩🇪

    We present a systematic global analysis of dineutrino modes $b\to q\nu \bar{\nu }$, $q=d,s$, and charged dilepton $b\to q{\ell }^{+}{\ell }^{-}$ transitions. We derive improved or even entirely new limits on dineutrino branching ratios including decays $B^0\to (K^0,X_s)\nu \bar{\nu }$, $B_s\to \varphi \nu \bar{\nu }$ and $B^0\to ({\pi }^0,{\rho }^0)\nu \bar{\nu }$ from dineutrino modes which presently are best constrained: $B^{+}\to (K^{+},{\pi }^{+},{\rho }^{+})\nu \bar{\nu }$ and $B^0\to K^{\ast 0}\nu \bar{\nu }$. Using SMEFT we obtain new flavor constraints from the dineutrino modes, which are stronger than the corresponding ones from charged dilepton rare $b$-decay or Drell-Yan data, for $e\tau$ and $\tau \tau$ final states, as well as for $\mu \tau$ ones in $b\to s$ processes. The method also allows to put novel constraints on semileptonic four-fermion operators with top quarks. Implications for ditau modes $b\to s{\tau }^{+}{\tau }^{-}$ and $b\to d{\tau }^{+}{\tau }^{-}$ are worked out. Furthermore, the interplay between dineutrinos and charged dileptons allows for concrete, novel tests of lepton universality in rare $B$-decays. Performing a global fit to $b\to s{\mu }^{+}{\mu }^{-},s\gamma$ transitions we find that lepton universality predicts the ratio of the $B^0\to K^{\ast 0}\nu \bar{\nu }$ to $B^0\to K^0\nu \bar{\nu }$ ($B^{+}\to K^{+}\nu \bar{\nu }$) branching fractions to be within 1.7 to 2.6 (1.6 to 2.4) at $1\sigma$, a region that includes the standard model, and that can be narrowed with improved charged dilepton data. There is sizable room outside this region where universality is broken and that can be probed with the Belle II experiment. Using results of a fit to $B^0\to {\mu }^{+}{\mu }^{-}$, $B_s^0\to {\bar{K}}^{\ast 0}{\mu }^{+}{\mu }^{-}$ and $B^{+}\to {\pi }^{+}{\mu }^{+}{\mu }^{-}$ data we obtain an analogous relation for $|\Delta b|=|\Delta d|=1$ transitions.

    hep-phhep-exJHEP(2021)·81 citations
18. 18*

    Jet Timing

    Wen Han Chiu🇺🇸 · Zhen Liu🇺🇸 · Matthew Low🇺🇸 · Lian-Tao Wang🇺🇸

    The measurement of the arrival time of a particle, such as a lepton, a photon, or a pion, reaching the detector provides valuable information. A similar measurement for a hadronic final state, however, is much more challenging as one has to extract the relevant information from a collection of particles. In this paper, we explore various possibilities in defining the time of a jet through the measurable arrival times of the jet constituents. We find that a definition of jet time based on a transverse momentum weighted sum of the times of the constituents has the best performance. For prompt jets, the performance depends on the jet trajectory. For delayed jets, the performance depends on the trajectory of the jet, the trajectory of the mother particle, and the location of the displaced vertex. Compared to the next-best-performing jet time definition, the transverse momentum weighted sum has roughly a factor of ten times better jet time resolution. We give a detailed discussion of the relevant effects and characterize the full geometrical dependence of the performance. These results highlight the critical importance of using a proper definition of jet time with its corresponding detector-dependent calibration and the exciting possibility of deepening our understanding of jets in the time domain.

    hep-phJHEP(2022)·14 citations
19. 19*

    Diluted Axion Star Collisions with Neutron Stars

    Yang Bai🇺🇸 · Xiaolong Du🇺🇸 · Yuta Hamada🇺🇸

    Diluted axion star, a self-gravitating object with the quantum pressure balancing gravity, has been predicted in many models with a QCD axion or axion-like particle. It can be formed in the early universe and composes a sizable fraction of dark matter. One could detect the transient radio signals when it passes by a magnetar with the axion particle converted into photon in the magnetic field. Using both numerical and semi-analytic approaches, we simulate the axion star's dynamic evolution and estimate the fraction of axion particles that can have a resonance conversion during such a collision event. We have found that both self-gravity and quantum pressure are not important after the diluted axion star enters the Roche radius. A free-fall approximate can capture individual particle trajectories very well. With some optimistic cosmological and astrophysical assumptions, the QCD axion parameter space can be probed from detecting such a collision event by radio telescopes.

    ↳ astro-ph.COhep-phJCAP(2022)·22 citations
20. 20*

    Diffusion matrix associated with the diffusion processes of multiple conserved charges in a hot and dense hadronic matter

    Arpan Das🇵🇱 · Hiranmaya Mishra🇮🇳 · Ranjita K. Mohapatra🇮🇳

    Bulk matter produced in heavy ion collisions has multiple conserved quantum numbers like baryon number, strangeness and electric charge. The diffusion process of these charges can be described by a diffusion matrix describing the interdependence of diffusion of different charges. The diffusion coefficient matrix is estimated here from the Boltzmann kinetic theory for the hadronic phase within relaxation time approximation. In the derivation for the same, we impose the Landau-Lifshitz conditions of fit. This leads to e.g. the diagonal diffusion coefficients to be manifestly positive definite. The explicit calculations are performed within the ambit of hadron resonance gas model with and without excluded volume corrections. It is seen that the off-diagonal components can be significant to affect the charge diffusion in a fluid with multiple conserved charges. The excluded volume correction effects is seen to be not significant in the estimation of the elements of the diffusion matrix.

    ↳ nucl-thhep-phPRD(2022)·17 citations
21. 21*

    Generating Seed magnetic field à la Chiral Biermann battery

    Arun Kumar Pandey🇮🇳 · Sampurn Anand🇮🇳

    Cosmological and astrophysical observations indicate the presence of magnetic field over all scales. In order to explain these magnetic fields, it is assumed that there exists a seed magnetic field that gets amplified by dynamos. These seed fields may have been produced during inflation, at phase transitions, or some turbulent phase of the early universe. One well-known mechanism to get the seed field is the Biermann battery, which was originally discussed in the context of generation in an astrophysical object. Requirements for this mechanism to work are (i) non-zero gradient of the electron number density and pressure, (ii) they are non-parallel to each other. In the present article, we propose a similar mechanism to generate the seed field but in inhomogeneous chiral plasma. Our mechanism works, in presence of chiral anomaly, by the virtue of inhomogeneity in the chiral chemical potential and temperature. We will discuss various scenarios where inhomogeneities in the chemical potential and temperature can arise. We found that, depending on the epoch of generation, the strength of the seed magnetic fields varies from a few nano-Gauss (nG) to a few hundred nG.

    ↳ astro-ph.COastro-ph.HEhep-phPRD(2021)·2 citations
22. 22*

    Evidence of quadrupole and octupole deformations in ${}^{96}$Zr+${}^{96}$Zr and ${}^{96}$Ru+${}^{96}$Ru collisions at ultra-relativistic energies

    Chunjian Zhang🇺🇸 · Jiangyong Jia🇺🇸

    In the hydrodynamic model description of heavy ion collisions, the elliptic flow $v_2$ and triangular flow $v_3$ are sensitive to the quadrupole deformation ${\beta }_2$ and octupole deformation ${\beta }_3$ of the colliding nuclei. The relations between $v_n$ and ${\beta }_n$ have recently been clarified and were found to follow a simple parametric form. The STAR Collaboration have just published precision $v_n$ data from isobaric ${}^{96}$Ru+${}^{96}$Ru and ${}^{96}$Zr+${}^{96}$Zr collisions, where they observe large differences in central collisions $v_{2,\mathrm{Ru}}>v_{2,\mathrm{Zr}}$ and $v_{3,\mathrm{Ru}}<v_{3,\mathrm{Zr}}$. Using a transport model simulation, we show that these orderings are a natural consequence of ${\beta }_{2,\mathrm{Ru}}\gg {\beta }_{2,\mathrm{Zr}}$ and ${\beta }_{3,\mathrm{Ru}}\ll {\beta }_{3,\mathrm{Zr}}$. We reproduce the centrality dependence of the $v_2$ ratio qualitatively and $v_3$ ratio quantitatively, and extract values of ${\beta }_2$ and ${\beta }_3$ that are consistent with those measured at low energy nuclear structure experiments. STAR data provide the first direct evidence of strong octupole correlations in the ground state of ${}^{96}$Zr in heavy ion collisions. Our analysis demonstrates that flow measurements in high-energy heavy ion collisions, especially using isobaric systems, are a new precision tool to study nuclear structure physics.

    ↳ nucl-thhep-phnucl-exPRL(2022)·160 citations
23. 23*

    Quantization of gravity and finite temperature effects

    I. Y. Park🇺🇸

    Gravity is perturbatively renormalizable for the physical states which can be conveniently defined via foliation-based quantization. In recent sequels, one-loop analysis was explicitly carried out for Einstein-scalar and Einstein-Maxwell systems. Various germane issues and all-loop renormalizability have been addressed. In the present work we make further progress by carrying out several additional tasks. Firstly, we present an alternative 4D covariant derivation of the physical state condition by examining gauge choice-independence of a scattering amplitude. To this end, a careful dichotomy between the ordinary, and large gauge symmetries is required and appropriate gauge-fixing of the ordinary symmetry must be performed. Secondly, vacuum energy is analyzed in a finite-temperature setup. A variant optimal perturbation theory is implemented to two-loop. The renormalized mass determined by the optimal perturbation theory turns out to be on the order of the temperature, allowing one to avoid the cosmological constant problem. The third task that we take up is examination of the possibility of asymptotic freedom in finite-temperature quantum electrodynamics. In spite of the debates in the literature, the idea remains reasonable.

    ↳ hep-thgr-qchep-phParticles(2021)·8 citations
24. 24*

    Connecting the Extremes: A Story of Supermassive Black Holes and Ultralight Dark Matter

    Hooman Davoudiasl🇺🇸 · Peter B. Denton🇺🇸 · Julia Gehrlein🇺🇸

    The formation of ultra rare supermassive black holes (SMBHs), with masses of $\mathcal{O}(10^9{M}_{\odot })$, in the first billion years of the Universe remains an open question in astrophysics. At the same time, ultralight dark matter (DM) with mass in the vicinity of $\mathcal{O}(10^{-20}\text{eV})$ has been motivated by small scale DM distributions. Though this type of DM is constrained by various astrophysical considerations, certain observations could be pointing to modest evidence for it. We present a model with a confining first order phase transition at $\sim 10$ keV temperatures, facilitating production of $\mathcal{O}(10^9{M}_{\odot })$ primordial SMBHs. Such a phase transition can also naturally lead to the implied mass for a motivated ultralight axion DM candidate, suggesting that SMBHs and ultralight DM may be two sides of the same cosmic coin. We consider constraints and avenues to discovery from superradiance and a modification to $N_{\mathrm{eff}}$. On general grounds, we also expect primordial gravitational waves -- from the assumed first order phase transition -- characterized by frequencies of $\mathcal{O}(10^{-12}-10^{-9}\text{Hz})$. This frequency regime is largely uncharted, but could be accessible to pulsar timing arrays if the primordial gravitational waves are at the higher end of this frequency range, as could be the case in our assumed confining phase transition.

    ↳ astro-ph.COhep-phPRL(2022)·24 citations
25. 25*

    Generation flow in field theory and strings

    Saul Ramos-Sanchez🇲🇽 · Michael Ratz🇺🇸 · Yuri Shirman🇺🇸 · Shreya Shukla🇺🇸 · Michael Waterbury🇺🇸

    Nontrivial strong dynamics often leads to the appearance of chiral composites. In phenomenological applications, these can either play the role of Standard Model particles or lift chiral exotics by partnering with them in mass terms. As a consequence, the RG flow may change the effective number of chiral generations, a phenomenon we call generation flow. We provide explicit constructions of globally consistent string models exhibiting generation flow. Since such constructions were misclassified in the traditional model searches, our results imply that more care than usually appreciated has to be taken when scanning string compactifications for realistic models.

    ↳ hep-thhep-phJHEP(2021)·4 citations
26. 26*

    Measurements of $q^2$ Moments of Inclusive $B\to X_c{\ell }^{+}{\nu }_{\ell }$ Decays with Hadronic Tagging

    Belle Collaboration: R. van Tonder🇩🇪 · L. Cao🇩🇪 · W. Sutcliffe🇩🇪 · M. Welsch🇩🇪 · F. U. Bernlochner🇩🇪 · I. Adachi🇯🇵 · H. Aihara🇯🇵 · D. M. Asner🇺🇸 · T. Aushev🇷🇺 · R. Ayad🇸🇦 · V. Babu🇩🇪 · P. Behera🇮🇳 and 192 other authors

    We present the measurement of the first to fourth order moments of the four-momentum transfer squared, $q^2$, of inclusive $B\to X_c{\ell }^{+}{\nu }_{\ell }$ decays using the full Belle data set of 711 ${\mathrm{fb}}^{-1}$ of integrated luminosity at the ${\rm Y}(4S)$ resonance where $\ell =e,\mu$. The determination of these moments and their systematic uncertainties open new pathways to determine the absolute value of the CKM matrix element $V_{cb}$ using a reduced set of matrix elements of the heavy quark expansion. In order to identify and reconstruct the $X_c$ system, we reconstruct one of the two $B$-mesons using machine learning techniques in fully hadronic decay modes. The moments are measured with progressively increasing threshold selections on $q^2$ starting with a lower value of 3.0 ${\mathrm{GeV}}^2$ in steps of 0.5 ${\mathrm{GeV}}^2$ up to a value of 10.0 ${\mathrm{GeV}}^2$. The measured moments are further unfolded, correcting for reconstruction and selection effects as well as QED final state radiation. We report the moments separately for electron and muon final states and observe no lepton flavor universality violating effects.

    ↳ hep-exhep-phPRD(2021)·63 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.