We propose the mass-varying dark matter (MVDM) model consisting of a scalar field and a fermionic field interacting via a simple Yukawa coupling and containing an exponential self-interaction potential for the scalar field. Analyzing the evolution of this coupled scalar-fermion system in an expanding Universe, we find that it initially behaves like radiation but then undergoes a phase transition after which it behaves like pressureless dark matter. The one free parameter of this model is the temperature at which the phase transition occurs; the mass of the dark matter particle, given by the mass of the fermion, is derived from this. For a phase-transition temperature between 10 MeV and ${10}^7\mathrm{GeV}$, the current dark matter relic density is achieved for a fermion mass in the range of $1–{10}^9\mathrm{GeV}$. In this dark matter model, the scalar becomes a subdominant unclustered component of dark matter that can lower the amplitude of structure formation by up to a few percent. Another feature is that the mass-varying fermion component can lead to discrepant measurements of the current dark matter density of about 10% inferred from early- and late-time probes assuming $\mathrm{\Lambda CDM}$.

We derive the total helicity conservation law for a perfect electromagnetic relativistic fluid. As the conservation equation contains the derivative of the magnetic helicity, it can be reshaped as having the same form as the chiral anomaly equation if the fluid is isentropic. We also take the nonrelativistic limit of the helicity conservation law, and check the agreement with the Abanov-Wiegmann equation at zero temperature, but we provide further corrections in the more general case. We then consider chiral fluids, when the chiral anomaly equation has to be incorporated in the hydrodynamical equations, together with other chiral transport effects which exist in the presence of a chiral imbalance. We finally study how the chiral imbalance modifies the helicity conservation law.

Predictions are made for the jet substructure of one-jet events produced in positron-proton neutral current deep inelastic scattering at the future Electron-Ion Collider for exchanged four-momentum squared, $Q^2>125{\mathrm{GeV}}^2$. Data are simulated using Monte Carlo event generators pythia 8.304 and rapgap 3.308 at the center of mass energies $\sqrt{s}=63.2$, 104.9, and 141 GeV. Jets and subjets are produced by longitudinally invariant $k_T$ cluster algorithm. The subjet multiplicity distributions and differential jet shapes are measured for different jet sizes and varying jet-resolution parameter. A comparison is presented between the $k_T$ and anti-$k_T$ cluster algorithms for the study of jets and subjets using the simulated data and the HERA data.

In this study, we introduce a model to illustrate neutrino phenomenology by incorporating two right-handed fermion triplet superfields, i.e., ${\mathrm{\Sigma }}_{R_j}$, in the presence of the modular symmetry ${\mathrm{\Gamma }}_3^{\prime }\simeq A_4^{\prime }$, a double cover of the $A_4$ modular symmetry. The motivation in utilizing double cover is that, so far, only even modular forms have been considered for constructing modular invariant models, but, in this case, it is possible to extend the modular invariance approach to general integral weight modular forms, i.e., the odd weight modular forms. Hence, this type of amalgamation between $T^{\prime }$ modular symmetry and minimally extending the seesaw can correctly explain the neutrino phenomenology. Additionally, we accommodate the most recent measurement of the $W$-boson mass, published by the CDF-II Collaboration, and shed some light on the recent results of muon ($g-2$). Finally, we discuss lepton flavor violation in order to establish a constraint on the mass of right-handed fermion.

The correlation functions of meson interpolators in $N_f=2+1+1$ lattice QCD with optimal domain-wall quarks at the physical point are studied for six temperatures in the range $T\sim 190–770\mathrm{MeV}$. The meson interpolators include a complete set of Dirac bilinears, and each for six combinations of quark flavors. In this paper, we focus on the meson correlators of $u$ and $d$ quarks, and we discuss their implications for the effective restoration of $U(1{)}_A$ and $SU(2{)}_L\times SU(2{)}_R$ chiral symmetries, as well as the emergence of approximate $SU(2{)}_{\mathrm{CS}}$ chiral spin symmetry.

We investigate the nontrivial 3-momentum effects on the masses of heavy quarkonium states that are moving in a hot medium using QCD sum rules. For all charmonium states, we observe a negative mass shift near $T_c$ that is less than 3% at a momentum of 1 GeV. Specifically, we first investigate the difference between the longitudinal and transverse modes of both $J/\psi$ and ${\chi }_{c1}$. We find that the transverse mode of the $J/\psi$ experiences larger modification than the longitudinal mode, while the ${\chi }_{c1}$ has the opposite behavior. By comparing the ${\eta }_c$ and ${\chi }_{c0}$, and also the unpolarized $J/\psi$ and ${\chi }_{c1}$, we recognize that the P-wave particles have stronger momentum dependencies on their masses than the S-wave ones. We also find $\mathrm{\Upsilon }(1\mathrm{S})$ has negligible 3-momentum dependence compared to the charmonium states, e.g., less than 0.01% even at $1.4T_c$ and at a momentum of 4 GeV.

The aim of this research is to investigate the vacuum energy-momentum tensor of a quantized, massive, nonminimally coupled scalar field induced by a uniform electric field background in a four-dimensional de Sitter spacetime (${\mathrm{dS}}_4$). We compute the expectation value of the energy-momentum tensor in the in-vacuum state and then regularize it using the adiabatic subtraction procedure. The correct trace anomaly of the induced energy-momentum tensor that confirmed our results is significant. The nonconservation equation for the induced energy-momentum tensor imposes the renormalization condition for the induced electric current of the scalar field. The findings of this research indicate that there are significant differences between the two induced currents which are regularized by this renormalization condition and the minimal subtraction condition.

This paper investigates the quasinormal mode (QNM) vibrations of a rotating cylindrical black hole (or black string) spacetime that is surrounded by a thin shell rotating synchronously with the black string’s axis. The existence of the thin shell leads to a piecewise metric of the black hole spacetime beyond the horizon, which is divided into two stationary spacetime parts by the radius of the thin shell. As a result, the potential function $V(r)$ of the QNM equation is also discontinuous. To solve the QNM equation with the discontinuous potential function, we propose two methods, the matrix method and the generalized Horowitz-Hubeny method. We find that the influence of the thin shell can reduce the QNM frequency of the black string while alleviating their amplitude decay rate. Our suggested method can be easily applied to other QNM calculations of black hole spacetime with discontinuous potential function, thus facilitating investigations into more intricate and realistic black hole spacetimes, such as those with accretion disks. Additionally, the finite difference method is employed to investigate the spacetime too. This analysis discloses a substantial gap in the potential function when the thin shell’s mass and charge achieve sufficiently high values, resulting in the outer spacetime nearing gravitational collapse and extreme black hole scenarios. Within this gap, the QNM wave displays oscillations, producing an echo effect. Moreover, it is established that the closeness of the spacetime to the collapse threshold and charge extremality have positive correlation with the beat interval of this echo.

We study the Dirac equation minimally coupled to general relativity using quantum field theory and the semiclassical gravity approximation. Previous studies of the Einstein-Dirac system did not quantize the Dirac field and required multiple independent Dirac fields to preserve spherical symmetry. We canonically quantize a single Dirac field in a static spherically symmetric curved spacetime background. Using the semiclassical gravity approximation, in which the Einstein field equations are sourced by the expectation value of the stress-energy-momentum tensor, we derive a system of equations whose solutions describe static spherically symmetric self-gravitating configurations of identical quantum spin-$1/2$ particles. We self-consistently solve these equations and present example configurations. Although limiting cases of our semiclassical system of equations reproduce the multifield system of equations found in the literature, our system of equations is derived from the excitations of a single quantum field.

Within the quark nugget model, dark matter particles may be represented by compact composite objects composed of a large number of quarks or antiquarks. Due to strong interaction with visible matter, antiquark nuggets should manifest themselves in a form of rare atmospheric events on the Earth. They may produce ionized trails in the atmosphere similar to the meteor trails. There are, however, several features which should allow one to distinguish antiquark nugget trails from the meteor ones. We study properties of ionized trails from antiquark nuggets in the air and show that they may be registered by standard meteor radar detectors. Nonobservation of such trails pushes up the mean baryon charge number in the quark nugget model, $|B|>4\times {10}^{27}$.

Broadband time-ordered data obtained from telescopes with a wavelength-dependent, asymmetric beam pattern can be used to extract maps at multiple wavelengths from a single scan. This technique is especially useful when collecting data on cosmic phenomena such as the cosmic microwave background (CMB) radiation, as it provides the ability to separate the CMB signal from foreground contaminants. We develop a method to determine the optimal linear combinations of wavelengths (“colors”) that can be reconstructed for a given telescope design and the number of colors that are measurable with high signal-to-noise ratio. The optimal colors are found as eigenvectors of a matrix derived from the inverse noise covariance matrix. When the telescope is able to scan the sky isotropically, it is useful to transform to a spherical harmonic basis, in which this matrix has a particularly simple form. We propose using the optimal colors determined from the isotropic case even when the actual scanning pattern is not isotropic (e.g., covers only part of the sky). We perform simulations showing that maps in multiple colors can be reconstructed accurately from both full-sky and partial-sky scans. Although the original motivation for this research comes from mapping the CMB, this method of polychromatic mapmaking will have broader applications throughout astrophysics.

As a follow-up study of our previous work [Phys. Rev. D 106, 023008 (2022)], numerical-relativity simulations for seconds-long black hole-neutron star mergers are performed for a variety of setups. Irrespective of the initial and symmetry conditions, we find qualitatively universal evolution processes: The dynamical mass ejection takes place together with a massive accretion disk formation after the neutron star is tidally disrupted; subsequently, the magnetic field in the accretion disk is amplified by the magnetic winding, Kelvin-Helmholtz instability, and magnetorotational instability, which establish a turbulent state inducing the dynamo and angular momentum transport; the postmerger mass ejection by the effective viscous processes stemming from the magnetohydrodynamics turbulence sets in at $\sim 300–500\mathrm{ms}$ after the merger and continues for several hundred ms; a magnetosphere near the black-hole spin axis is developed and the collimated strong Poynting flux is generated with its lifetime of $\sim 0.5–2\mathrm{s}$. We have newly found that the model of no equatorial-plane symmetry shows the reverse of the magnetic-field polarity in the magnetosphere, which is caused by the dynamo associated with the magnetorotational instability in the accretion disk. The model with initially toroidal fields shows the tilt of the disk and magnetosphere in the late postmerger stage because of the anisotropic postmerger mass ejection. These effects could terminate the strong Poynting-luminosity stage within the timescale of $\sim 0.5–2\mathrm{s}$.

In this paper, we present a CT18 PDF global QCD analysis at leading order in QCD perturbation theory. The CT18 LO PDFs is obtained within the general CT18 framework, along with two additional procedures imposed to improve the quality of the fit. We take the $W$-boson charge asymmetry and inclusive single-top production at LHC as examples to illustrate implications of the CT18 LO PDFs.

Heavy neutrinos from the type-I seesaw model can have a large mixing with active states, motivating their search at collider experiments. However, loop corrections to light neutrino masses constrain the heavy neutrinos to appear in pseudo-Dirac pairs, leading to a potential suppression of lepton number violating parameters. In this work we perform a detailed review of a proposal to relax constraints on lepton number violation by adding supersymmetry (SUSY). We define the conditions necessary to maximize the SUSY screening effect, with the objective of allowing a larger mass splitting between low-scale heavy neutrino masses. We find that the sole addition of SUSY does not guarantee a screening, and that favorable cases have some degree of fine-tuning.

In this work, we formulate the theory of Lorentz-violating scalar quantum chromodynamics with an arbitrary non-Abelian gauge group. This theory belongs to the class of models encompassed by the standard model extension framework. At the lowest order in the theory’s Lorentz violation parameters, we calculate the divergent quantum corrections, including the renormalization group $\beta$-functions of the theory. The Lorentz-violating sector is shown to be scale invariant if there is a particular relation between the couplings.

The presence of a new decay mode relaxes the current mass exclusion limits on vectorlike quarks considerably. We consider the case of a weak-singlet vectorlike $B$ quark that can decay to a singlet scalar or pseudoscalar $\mathrm{\Phi }$. In an earlier paper [A. Bhardwaj et al., Roadmap to explore vectorlike quarks decaying to a new scalar or pseudoscalar, Phys. Rev. D, 106, 095014 (2022)], we mapped the possibilities to explore such setups at the LHC. We showed that it is possible for a $B$ quark to decay into $\mathrm{\Phi }$ and the $\mathrm{\Phi }$ to dominantly decay to a pair of gluons or $b$ quark(s) without fine-tuning the parameters. In this paper, we present a collider search strategy to look for the pair production of singlet $B$ quarks. If both $B$’s decay into $b\mathrm{\Phi }$ pairs, the final state is fully hadronic: $BB\to (b\mathrm{\Phi })(b\mathrm{\Phi })\to (bgg)(bgg)/(bbb)(bbb)$, which is very challenging to probe. Therefore, we consider a simpler mixed decay specific to the singlet $B$ case, $BB\to (b\mathrm{\Phi })(tW)$ with a lepton in the final state, to achieve the best sensitivity at the high-luminosity LHC. We use a deep neural network with a weighted cross-entropy loss to separate the signal from the huge Standard Model background. Our analysis shows that large areas of the $M_B-M_{\mathrm{\Phi }}$ parameter space are discoverable through this signature. We show how the discovery and exclusion regions scale with the branching ratio in the new decay mode. We also estimate the reach in the inclusive monolepton channel with the same network model.

The isolation of pure samples of quark and gluon jets is of key interest at hadron colliders. Recent work has employed topic modeling to disentangle the underlying distributions in mixed samples obtained from experiments. However, current implementations do not scale to high-dimensional observables as they rely on binning the data. In this work we introduce TopicFlow, a method based on normalizing flows to learn quark and gluon jet topic distributions from mixed datasets. These networks are as performant as the histogram-based approach, but since they are unbinned, they are efficient even in high dimension. The models can also be oversampled to alleviate the statistical limitations of histograms. As an example use case, we demonstrate how our models can improve the calibration accuracy of a classifier. Finally, we discuss how the flow likelihoods can be used to perform outlier-robust quark/gluon classification.

Final states in collider experiments are characterized by correlation functions, $⟨\mathcal{E}({\overrightarrow{n}}_1)\cdots \mathcal{E}({\overrightarrow{n}}_k)⟩$, of the energy flow operator $\mathcal{E}({\overrightarrow{n}}_i)$. We show that the top quark imprints itself as a peak in the three-point correlator at an angle $\zeta \sim m_t^2/p_T^2$, with $m_t$ the top quark mass and $p_T$ its transverse momentum, providing access to one of the most important parameters of the Standard Model in one of the simplest field theoretical observables. Our analysis provides the first step toward a new paradigm for a precise top-mass determination that is, for the first time, highly insensitive to soft physics and underlying event contamination whilst remaining directly calculable from the Standard Model Lagrangian.

We present a detailed phenomenological study of $J/\psi$ polarization in semi-inclusive deep-inelastic scattering processes, focusing on the kinematics accessible at the future Electron-Ion Collider. We show theoretical estimates for the standard polarization parameters for different frames usually adopted in the literature, in the large $P_T$ region, namely $P_T\gg {\mathrm{\Lambda }}_{\mathrm{QCD}}$, where collinear factorization is expected to hold. We adopt both the color singlet model and the nonrelativistic QCD approach, paying special attention to the role of different sets of long distance matrix elements. Finally we present a preliminary analysis of some frame independent polarization invariants.

We investigate exotic neutrino interactions using the $205.4\text{−}\mathrm{kg}·\mathrm{day}$ dataset from the CDEX-10 experiment at the China Jinping Underground Laboratory. New constraints on the mass and couplings of new gauge bosons are presented. Two nonstandard neutrino interactions are considered: a $U(1{)}_{\mathrm{B}–\mathrm{L}}$ gauge-boson-induced interaction between an active neutrino and electron/nucleus, and a dark-photon-induced interaction between a sterile neutrino and electron/nucleus via kinetic mixing with a photon. This work probes an unexplored parameter space involving sterile neutrino coupling with a dark photon. New laboratory limits are derived on dark photon masses below $1\mathrm{eV}/c^2$ at some benchmark values of $\mathrm{\Delta }{m}_{41}^2$ and $g^{\prime 2}{\sin }^{2}2{\theta }_{14}$.