The cross sections of $J/\psi {\eta }_c$ and $J/\psi J/\psi$ production in $e^{+}{e}^{-}$ annihilation are calculated at a one-loop accuracy near $Z$-boson pole and at higher energies as well. Both intermediate bosons, $\gamma$ and $Z$, are included. It is found that at $Z$ mass, the next-to-leading contribution increases the production cross sections by a factor of 3.5.

We present a comprehensive impact study of future Electron-Ion Collider (EIC) data for parity-conserving and parity-violating polarization asymmetries on quark and gluon helicity distributions in the proton. The study, which is based on the JAM Monte Carlo global QCD analysis framework, explores the role of the extrapolation uncertainty and SU(3) flavor symmetry constraints in the simulated double-spin asymmetry, $A_{LL}$, at small parton momentum fractions $x$ and its effect on the extracted parton polarizations. We find that different assumptions about $A_{LL}$ extrapolations and SU(3) symmetry can have significant consequences for the integrated quark and gluon polarizations, for polarized proton, deuteron, and ${}^3\mathrm{He}$ beams. For the parity-violating asymmetry, $A_{UL}$, we study the potential impact on the polarized strange quark distribution with different extrapolations of $A_{UL}$, finding the constraining power to be ultimately limited by the EIC machine luminosity.

The Born cross sections are measured for the first time for the processes $e^{+}{e}^{-}\to D_s^{*+}{D}_{s0}^{*}(2317{)}^{-}+\mathrm{c}.\mathrm{c}.$ and $e^{+}{e}^{-}\to D_s^{*+}{D}_{s1}(2460{)}^{-}+\mathrm{c}.\mathrm{c}.$ at the center-of-mass energy $\sqrt{s}=4.600\mathrm{GeV}$, 4.612 GeV, 4.626 GeV, 4.640 GeV, 4.660 GeV, 4.68 GeV, and 4.700 GeV, and for $e^{+}{e}^{-}\to D_s^{*+}{D}_{s1}(2536{)}^{-}+\mathrm{c}.\mathrm{c}.$ at $\sqrt{s}=4.660\mathrm{GeV}$, 4.680 GeV, and 4.700 GeV, using data samples collected with the BESIII detector at the BEPCII collider. No structures are observed in cross-section distributions for any of the processes.

The first amplitude analysis of the decay $D_s^{+}\to K^{-}{K}^{+}{\pi }^{+}{\pi }^0$ is presented using the data samples, corresponding to an integrated luminosity of $6.32{\mathrm{fb}}^{-1}$, collected with the BESIII detector at $e^{+}{e}^{-}$ center-of-mass energies between 4.178 and 4.226 GeV. More than 3000 events selected with a purity of 97.5% are used to perform the amplitude analysis, and nine components are found necessary to describe the data. Relative fractions and phases of the intermediate decays are determined. With the detection efficiency estimated by the results of the amplitude analysis, the branching fraction of $D_s^{+}\to K^{-}{K}^{+}{\pi }^{+}{\pi }^0$ decay is measured to be $(5.42\pm 0.10_{\mathrm{stat}}\pm 0.17_{\mathrm{syst}})\%$.

We extend Kodama-Ishibashi and Jansen-Rostworowski-Rutkowski master field framework to study quasinormal modes of black branes and black holes of Einstein gravity in $D=5$ space-time dimensions with multiple scalars and an arbitrary bulk potential. As an application, we consider a thermodynamically unstable state of mass deformed $\mathcal{N}=4$ supersymmetric Yang-Mills theory at strong coupling. The corresponding gravitational dual is $\mathcal{N}=2^{*}$ black brane with a dynamical instability of its translationary invariant horizon. We study the dependence of the quasinormal mode spectra as the boundary gauge theory is compactified on $S^3$—the black brane is turned into the black hole.

In this paper, we study quantum vacuum fluctuation effects on the mass density of a classical liquid arising from the conical topology of an effective idealized cosmic string spacetime, as well as from the mixed, Dirichlet, and Neumann boundary conditions in Minkowski spacetime. In this context, we consider a phonon field representing quantum excitations of the liquid density, which obeys an effective Klein-Gordon equation with the sound velocity replaced by the light velocity. In the idealized cosmic string spacetime, the phonon field is subject to a quasiperiodic condition. Moreover, in Minkowski spacetime, the Dirichlet and Neumann boundary conditions are applied on one and also on two parallel planes. We thus, in each case, obtain closed analytic expressions for the two-point function and the renormalized mean squared density fluctuation of the liquid. We point out specific characteristics of the latter by plotting their graphs.

We study a special two-dimensional dilaton gravity with Lagrangian $\mathcal{L}=\frac{1}{2}\sqrt{-g}(\varphi R+{\lambda }^2{\mathrm{sech}}^2\varphi )$ where $\lambda$ is a parameter of dimension mass. This theory describes two-dimensional spacetimes that are asymptotically flat. Very interestingly, it has an exact solution for the metric, $\mathrm{d}{s}^2=-(c+\tanh \lambda x)\mathrm{d}{t}^2+\mathrm{d}{x}^2/(c+\tanh \lambda x)$, parametrized by $c$. For $c\in (-1,1)$, the solution presents an event horizon but no singularity. Because of the kink profile for the metric components appearing in the solution, we refer to the spacetime described by the metric as a gravitational domain wall with the wall simply being the event horizon and separating two asymptotically Minkowskian spacetimes. The global causal structure for such an object is studied via coordinate extension and the thermodynamical quantities are computed. Only when $c\in (-1,0]$ are the entropy and energy non-negative.

We construct a new set of asymptotically flat, static vacuum solutions to the Einstein equations in dimensions 4 and 5, which may be interpreted as a superposition of positive and negative mass black holes. The resulting spacetimes are axisymmetric in 4-dimensions and biaxisymmetric in 5-dimensions, and are regular away from the negative mass singularities, for instance conical singularities are absent along the axes. In 5-dimensions, the topologies of signed mass black holes used in the construction may be either spheres $S^3$ or rings $S^1\times S^2$; in particular, the negative mass static black ring solution is introduced. A primary observation that facilitates the superposition is the fact that, in Weyl-Papapetrou coordinates, negative mass singularities arise as overlapping singular support for a particular type of Green’s function. Furthermore, a careful analysis of conical singularities along axes is performed, and formulas are obtained for their propagation across horizons, negative mass singularities, and corners. The methods are robust, and may be used to construct a multitude of further examples. Lastly, we show that balancing does not occur between any two signed mass black holes of the type studied here in 4 dimensions, while in 5 dimensions two-body balancing is possible.

The fast radio bursts (FRBs) are energetic radio bursts with millisecond duration only observed at radio frequencies. The generation mechanism is still mysterious. We have proposed a generation mechanism of both repeating and one-off FRBs. They arise from axion star collision with a neutron star or a magnetized accretion disk of a galactic black hole. Once we accept the existence of the axions, we find that the mechanism well explained previously observed spectral-temporal features. In this paper we show that it also explains recently observed phenomena such as downward drifting in the repeating FRBs, etc. Analysis of the downward drifting based on Doppler effects has been presented in recent papers, in which a superradiance system of molecular or atom has been proposed as a source of FRBs. We apply the analysis to our mechanism and find that it well explains the relation between the downward drifting rate and the duration of the repeating FRBs. The Doppler effects lead to the fact that the duration of radio burst with higher center frequency is shorter than that of radio burst with lower center frequency in the repeating FRBs. Our generation mechanism naturally explains polarization angle swing observed in the repeating FRB180301 and one-off FRBs. We also discuss the association between the FRB200428 and magnetar SGR $\mathrm{J}1935+2154$. The x-ray burst observed just after the observation of the FRB could be triggered by the axion star collision with the magnetar. We also explain the consistency of our generation mechanism with observed spectral-temporal differences in the repeating and one-off FRBs, e.g., longer duration (smaller luminosity) of repeating FRBs than duration (luminosity) of one-off FRBs.

The KAGRA gravitational-wave detector in Japan is the only operating detector hosted in an underground infrastructure. Underground sites promise a greatly reduced contribution of the environment to detector noise thereby opening the possibility to extend the observation band to frequencies well below 10 Hz. For this reason, the proposed next-generation infrastructure Einstein Telescope in Europe would be realized underground aiming for an observation band that extends from 3 Hz to several kHz. However, it is known that ambient noise in the low-frequency band 10 Hz–20 Hz at current surface sites of the Virgo and LIGO detectors is predominantly produced by the detector infrastructure. It is of utmost importance to avoid spoiling the quality of an underground site with noisy infrastructure, at least at frequencies where this noise can turn into a detector-sensitivity limitation. In this paper, we characterize the KAGRA underground site to determine the impact of its infrastructure on environmental fields. We find that while excess seismic noise is observed, its contribution in the important band below 20 Hz is minor preserving the full potential of this site to realize a low-frequency gravitational-wave detector. Moreover, we estimate the Newtonian-noise spectra of surface and underground seismic waves and of the acoustic field inside the caverns. We find that these will likely remain a minor contribution to KAGRA’s instrument noise in the foreseeable future.

In this work, we discuss exclusive semileptonic $B_c$-meson decays: $B_c\to {\eta }_c(J/\psi )l\nu$ and $B_c\to D(D^{*})l\nu$ in the framework of the relativistic independent quark (RIQ) model based on an average flavor independent confining potential in equally mixed scalar-vector harmonic form. We calculate the invariant form factors representing decay amplitudes from the overlapping integrals of meson wave functions derivable in the RIQ model. To evaluate the lepton mass effects in the semileptonic decays, we first study the $q^2$-dependence of the form factors in the accessible kinematic range of $q^2$ involved in the decay process in its $e^{-}$ and ${\tau }^{-}$ mode separately. Similar studies on helicity amplitudes, $q^2$—spectra for different helicity contributions, and total $q^2$-spectra for each decay process are carried out separately in their $e^{-}$ and ${\tau }^{-}$ modes. We predict the decay rates/ branching fractions, forward-backward asymmetry, and the asymmetry parameter in reasonable agreement with other model predictions, which can hopefully be tested in future experiments at the Tevatron and LHC. We also predict the observable ${}^{\prime }{R}^{\prime }$ which corresponds to the ratio of branching fractions for the decay process in its $e^{-}$ mode to its corresponding value in the ${\tau }^{-}$ mode. Our results are comparable to other standard model(SM) predictions which highlight the failure of the lepton flavor universality hinting at new physics beyond SM for the explanation of the observed deviation of observable ${}^{\prime }{R}^{\prime }$ value from the corresponding SM predictions.

Baryon number is an accidental symmetry in the standard model, while Peccei-Quinn symmetry is hypothetical symmetry which is introduced to solve the strong $CP$ problem. We study the possible connections between Peccei-Quinn symmetry and baryon number symmetry. In this framework, an axion is identified as the Nambu-Goldstone boson of baryon number violation. As a result, characteristic baryon number violating processes are predicted. We developed the general method to determine the baryon number and lepton number of new scalar in the axion model.

We study the early kinetic decoupling effect in a pseudo-Nambu-Goldstone (pNG) dark matter (DM) model. The pNG DM scattering processes with particles in the thermal bath in the early Universe are suppressed by the small momentum transfer. As a result, kinetic equilibrium is not maintained, and the temperature of DM is different from the temperature of the thermal bath at the freeze-out era. This temperature difference affects the thermal relic abundance of DM. We investigate the early kinetic decoupling in the Higgs resonance region, $50\mathrm{GeV}\lesssim m_{\chi }\lesssim m_h/2$, where $m_{\chi }$ is the mass of the DM, and $m_h/2\simeq 62.5\mathrm{GeV}$. We find that the DM-Higgs coupling determined to obtain the measured value of the DM energy density is underestimated in the literature. The enhancement in the coupling leads larger value of the Higgs invisible decay rate. It enlarges the capability to discover the DM signals from the decay of the Higgs bosons at collider experiments.

We study the implication of $J/\psi$ decay into invisible particles for light sterile neutrino and sub-GeV dark matter (DM). The low-energy effective field theories (EFTs) are used for the description of general neutrino interactions and the Dirac fermion DM coupled to charm quark. For $J/\psi \to \gamma +\text{invisible}$, we perform the likelihood fits for the individual neutrino and DM operators with distinct Lorentz structures and photon spectra. The limits on the decay branching fractions are obtained for different neutrino or DM scenarios and then converted to the lower bounds on the new energy scales. The most stringent bounds on the energy scale in neutrino and DM EFTs are 12.8 GeV and 11.6 GeV, respectively. The purely invisible decay $J/\psi \to \text{invisible}$ provides complementary constraints on the effective operators. The relevant bound on the energy scale is above 100 GeV for the dipole operators. We also evaluate the limit on the DM-nucleon scattering cross section converted from $J/\psi$ data. The data of $J/\psi$ invisible decays are sensitive to the light DM mass range where the DM direct detection experiments cannot probe yet. The future Super Tau Charm Factory after one year run can push the limits down by two orders of magnitude.

We study the dynamics of chemical freeze-out of single strange hadrons—$K$, $\mathrm{\Lambda }$, $\mathrm{\Sigma }$, from a homogeneous and isotropically expanding system consisting of $\pi$, $K$, $\rho$, $N$, $\mathrm{\Lambda }$, and $\mathrm{\Sigma }$ hadrons with zero net baryon density. We use the momentum-integrated Boltzmann equation or rate equation to study the evolution of strange hadrons considering Bjorken and Hubble-like expansions. We calculate the scattering rates of $K$, $\mathrm{\Lambda }$, $\mathrm{\Sigma }$ and compare with the expansion rate to analyze the chemical freeze-out of these species. In this microscopic calculation the cross sections, which are input to the rate equation, are taken either from phenomenological models or are parametrized by comparing against experimental data. From this calculation it is found that these strange hadrons freeze out early near transition temperature $T_c$ when the system follows a Hubble-like fast expansion. But, for a slower Bjorken-like expansion, strange hadrons take a longer time to decouple following a sequential behavior. The present calculation may set a guideline to understand the common freeze-out behavior of strange hadron species at Relativistic Heavy Ion Collider(RHIC) and Large Hadron Collider(LHC), which is mostly predicted by thermal models while explaining the yields of identified particles.

We show that the cross section for diffractive dissociation of a small onium off a large nucleus at total rapidity $Y$ and requiring a minimum rapidity gap $Y_{\mathrm{gap}}$ can be identified, in a well-defined parametric limit, with a simple classical observable on the stochastic process representing the evolution of the state of the onium, as its rapidity increases, in the form of color dipole branchings: it formally coincides with twice the probability that an even number of these dipoles effectively participate in the scattering, when viewed in a frame in which the onium is evolved to the rapidity $Y-Y_{\mathrm{gap}}$. Consequently, finding asymptotic solutions to the Kovchegov-Levin equation, which rules the $Y$ dependence of the diffractive cross section, boils down to solving a probabilistic problem. Such a formulation authorizes the derivation of a parameter-free analytical expression for the gap distribution. Interestingly enough, events in which many dipoles interact simultaneously play an important role, since the distribution of the number $k$ of dipoles participating in the interaction turns out to be proportional to $1/[k(k-1)]$.

The work presents the study of the polarization observables in the single pion production (SPP) induced by the interaction of the muon neutrino (antineutrino) with nucleons. The SPP cross sections and spin asymmetries are computed within two phenomenological models. One is based on the nonlinear sigma model [E. Hernandez, J. Nieves, and M. Valverde, Phys. Rev. D 76, 033005 (2007)] and the other has origin in the linear sigma model [G. L. Fogli and G. Nardulli, Nucl. Phys. B160, 116 (1979)]. First, we show that the final nucleon polarization and target spin asymmetries are good observables to obtain information about the $C_5^A$ axial form factor. Second, we demonstrate that the nucleon polarization and the target spin asymmetries are sensitive to the relative phase between resonance and nonresonance amplitudes. We conclude that the polarization of the final nucleon and the target spin asymmetry are promising observables for testing SPP models, including studies of the axial content of $\mathrm{\Delta }(1232)$ resonance and unitarization procedures.

We discuss various aspects of a neutrino physics program that can be carried out with the neutrino Beam-Dump eXperiment DRIFT ($\nu \mathrm{BDX}\text{−}\mathrm{DRIFT}$) detector using neutrino beams produced in next generation neutrino facilities. $\nu \mathrm{BDX}\text{−}\mathrm{DRIFT}$ is a directional low-pressure time projection chamber detector suitable for measurements of coherent elastic neutrino-nucleus scattering ($\mathrm{CE}\nu \mathrm{NS}$) using a variety of gaseous target materials which include carbon disulfide, carbon tetrafluoride and tetraethyllead, among others. The neutrino physics program includes standard model measurements and beyond the standard model physics searches. Focusing on the Long Baseline Neutrino Facility beam line at Fermilab, we first discuss basic features of the detector and estimate backgrounds, including beam-induced neutron backgrounds. We then quantify the $\mathrm{CE}\nu \mathrm{NS}$ signal in the different target materials and study the sensitivity of $\nu \mathrm{BDX}\text{−}\mathrm{DRIFT}$ to measurements of the weak mixing angle and neutron density distributions. We consider as well prospects for new physics searches, in particular sensitivities to effective neutrino nonstandard interactions.

We present the design and characterization of a cryogenic phonon-sensitive 1-gram Si detector exploiting the Neganov-Trofimov-Luke effect to detect single-charge excitations. This device achieved 2.65(2) eV phonon energy resolution when operated without a voltage bias across the crystal and a corresponding charge resolution of 0.03 electron-hole pairs at 100 V bias. With a continuous-readout data acquisition system and an offline optimum-filter trigger, we obtain a 9.2 eV threshold with a trigger rate of the order of 20 Hz. The detector’s energy scale is calibrated up to 120 keV using an energy estimator based on the pulse area. The high performance of this device allows its application to different fields where excellent energy resolution, low threshold, and large dynamic range are required, including dark matter searches, precision measurements of coherent neutrino-nucleus scattering, and ionization yield measurements.

Events where the two leading jets are separated by a pseudorapidity interval devoid of particle activity, known as jet-gap-jet events, are studied in proton-proton collisions at $\sqrt{s}=13\mathrm{TeV}$. The signature is expected from hard color-singlet exchange. Each of the highest transverse momentum ($p_{\mathrm{T}}$) jets must have $p_{\mathrm{T}}^{\mathrm{jet}}>40\mathrm{GeV}$ and pseudorapidity $1.4<|{\eta }^{\mathrm{jet}}|<4.7$, with ${\eta }^{\mathrm{jet}1}{\eta }^{\mathrm{jet}2}<0$, where jet1 and jet2 are the leading and subleading jets in $p_{\mathrm{T}}$, respectively. The analysis is based on data collected by the CMS and TOTEM experiments during a low luminosity, high-${\beta }^{*}$ run at the CERN LHC in 2015, with an integrated luminosity of $0.66{\mathrm{pb}}^{-1}$. Events with a low number of charged particles with $p_{\mathrm{T}}>0.2\mathrm{GeV}$ in the interval $|\eta |<1$ between the jets are observed in excess of calculations that assume only color-exchange. The fraction of events produced via color-singlet exchange, $f_{\mathrm{CSE}}$, is measured as a function of $p_{\mathrm{T}}^{\mathrm{jet}2}$, the pseudorapidity difference between the two leading jets, and the azimuthal angular separation between the two leading jets. The fraction $f_{\mathrm{CSE}}$ has values of 0.4–1.0%. The results are compared with previous measurements and with predictions from perturbative quantum chromodynamics. In addition, the first study of jet-gap-jet events detected in association with an intact proton using a subsample of events with an integrated luminosity of $0.40{\mathrm{pb}}^{-1}$ is presented. The intact protons are detected with the Roman pot detectors of the TOTEM experiment. The $f_{\mathrm{CSE}}$ in this sample is $2.91\pm 0.70{(\mathrm{stat})}_{-1.01}^{+1.08}(\mathrm{syst})$ times larger than that for inclusive dijet production in dijets with similar kinematics.