We present the first detailed simulation study of tau neutrino-induced charged current events from atmospheric neutrino interactions in the Iron Calorimeter detector at the proposed India-based Neutrino Observatory laboratory. Since the intrinsic atmospheric neutrino flux at few to 10s of GeV energy comprises only electron and muon neutrinos (and antineutrinos) with a negligible tau neutrino component, any signature of atmospheric tau neutrinos is a signal for neutrino oscillations. We study the tau leptons produced through these charged current interactions via their hadronic decay. These events appear as an excess over the neutral current background where hadrons are the only observable component. We find that the presence of tau neutrinos in the atmospheric neutrino flux can be demonstrated to nearly $4\sigma$ confidence with 10 years of data; in addition, these events are sensitive to the neutrino oscillation parameters, ${\sin }^2{\theta }_{23}$ and $|\mathrm{\Delta }{m}_{31}^2|$ (or $|\mathrm{\Delta }{m}_{32}^2|$), in the 2–3 sector. Finally, we show that combining these events with the standard muon analysis which is the core goal of the Iron Calorimeter further improves the precision with which these parameters, especially the octant of ${\theta }_{23}$, can be measured.

We calculate the neutral current jet production semi-inclusive deeply inelastic scattering process in this paper. Neutral current implies that interactions can be mediated by the photon, $Z^0$ boson, and their interference. The initial electron is assumed to be polarized and then scattered off by a target particle with spin $1/2$. Calculations are carried out up to twist-3 level in the quantum chromodynamics parton model by applying the collinear expansion formalism where multiple gluon scattering is taken into account and gauge links are obtained automatically. After obtaining the differential cross section, we introduce the definition of the intrinsic asymmetry. This quantity reveals the asymmetry in the distribution of the quark intrinsic transverse momentum. We find that these asymmetries can be expressed in terms of the transverse momentum-dependent parton distribution functions and the electroweak couplings. As a result, our calculations provide a set of new quantities for analyzing the parton distribution functions and the electroweak couplings. It is helpful to understand the hadronic weak interactions and strong interactions in the deeply inelastic scattering process simultaneously.

We investigate inhomogeneous chiral condensation under rotation considering finite size effects and boundary conditions in the holographic QCD model. The rotational suppression effect determined by $\mathrm{\Omega }r$ is confirmed in the holographic model which is not influenced by the boundary conditions. For chiral condensation at the center, it is found that under Neumann boundary condition the finite size exhibits two opposite effects, i.e., catalysis at high temperatures and inverse catalysis at low temperatures. In contrast, under Dirichlet boundary condition, the effect of finite size on condensation is inverse catalysis, and small size induces a phase transition from inhomogeneous to homogeneous phase. The temperature-angular velocity phase diagrams of QCD are obtained for different boundary conditions and sizes, and it is found that the critical temperature decreases with angular velocity.

Recent measurements of gravitational-wave ringdown following the merger of binary black holes raise the prospect of precision black hole spectroscopy in the near future. To perform the most sensitive tests of the nature of black holes using ringdown measurements, it is critical to compute the deviations to the spectrum of black holes in particular extensions of relativity. These spectral shifts are also needed to interpret any violations of the predictions of relativity that may be detected during ringdown. Here we present a first step towards computing the shifts to the spectrum of Kerr black holes with arbitrary spins, by deriving a modified Teukolsky equation governing the perturbations of black holes in theories beyond general relativity. Our approach applies to a class of theories which includes dynamical Chern-Simons gravity and shift-symmetric scalar Gauss-Bonnet gravity, in the case where the deviations from relativity are small. This allows for a perturbative approach to solving the equations of motion. Further, we show how to use the modified equation to compute the leading-order spectral shifts of Kerr black holes, using eigenvalue perturbation methods. Our formalism provides a practical approach to predicting ringdown for black holes in a range of promising extensions to relativity, enabling future precision searches for their signatures in black hole ringdown.

Measurement of spin-precession in black hole binary mergers observed with gravitational waves is an exciting milestone as it relates to both general relativistic dynamics and astrophysical binary formation scenarios. In this study, we revisit the evidence for spin-precession in GW200129 and localize its origin to data in LIGO Livingston in the 20–50 Hz frequency range where the signal amplitude is lower than expected from a nonprecessing binary given all the other data. These data are subject to known data quality issues as a glitch was subtracted from the detector’s strain data. The lack of evidence for spin-precession in LIGO Hanford leads to a noticeable inconsistency between the inferred binary mass ratio and precessing spin in the two LIGO detectors, something not expected from solely different Gaussian noise realizations. We revisit the LIGO Livingston glitch mitigation and show that the difference between a spin-precessing and a nonprecessing interpretation for GW200129 is smaller than the statistical and systematic uncertainty of the glitch subtraction, finding that the support for spin-precession depends sensitively on the glitch modeling. We also investigate the signal-to-noise ratio $\sim 7$ trigger in the less sensitive Virgo detector. Though not influencing the spin-precession studies, the Virgo trigger is grossly inconsistent with the ones in LIGO Hanford and LIGO Livingston as it points to a much heavier system. We interpret the Virgo data in the context of further data quality issues. While our results do not disprove the presence of spin-precession in GW200129, we argue that any such inference is contingent upon the statistical and systematic uncertainty of the glitch mitigation. Our study highlights the role of data quality investigations when inferring subtle effects such as spin-precession for short signals such as the ones produced by high-mass systems.

The planned Laser Interferometric Space Antenna (LISA) will be able to detect gravitational waves (GWs) from intermediate mass binary black holes (IMBBHs) in the mass range $\sim {10}^2–{10}^4{M}_{\odot }$ up to a redshift $z\sim 20$. Modulation effects due to LISA’s orbital motion around the Sun facilitate precise premerger localization of the sources, which in turn would help in electromagnetic (EM) followups. In this work, we calculate the uncertainties in sky position, luminosity distance, and time of coalescence as a function of time to coalescence. For representative masses of the IMBBHs, we synthesize a population of binaries uniformly located and oriented on a sphere of radius 3 Gpc and compute the projected parameter measurement uncertainties using the Fisher information matrix. We find that for systems with a total mass of ${10}^3{M}_{\odot }$, the errors in the sky position and luminosity distance are $\sim 0.4{\mathrm{deg}}^2$ and $\sim 6\%$, respectively, one day prior to coalescence. The coalescence time can be predicted with an uncertainty $\lesssim 10\sec$, one day before coalescence. We also find that for ${10}^3{M}_{\odot }$, around 40% (100%) of the population has a source localization that is smaller than the field of view of Athena (LSST) one day before the merger. These extremely precise measurements can be used to alert ground-based GW detectors and EM telescopes about the time and location of these mergers. We also discuss mechanisms that may produce EM emission from IMBBH mergers and study its detectability using the planned Legacy Survey of Space and Time (LSST) in the optical and Athena in the x-ray bands. Detection of an EM transient may provide us vital clues about the environments where these mergers occur and the distance estimation can pave the way for cosmography.

Dense astrophysical environments like globular clusters and galactic nuclei can host hyperbolic encounters of black holes which can lead to gravitational-wave driven capture. There are several astrophysical models which predict a fraction of binary black hole mergers to come from these radiation-driven capture scenarios. In this paper, we present the sensitivity of a search toward gravitational-wave driven capture events for O3, the third observing run of LIGO and Virgo. We use capture waveforms produced by numerical relativity simulations covering four different mass ratios and at least two different values of initial angular momentum per mass ratio. We employed the most generic search for short-duration transients in O3 to evaluate the search sensitivity in this parameter space for a wide range in total mass in terms of visible spacetime volume. From the visible spacetime volume we determine for the first time the merger rate upper limit of such systems. The most stringent estimate of rate upper limits at 90% confidence is $0.2{\mathrm{Gpc}}^{-3}{\mathrm{yr}}^{-1}$ for an equal mass $200M_{\odot }$ binary. Furthermore, in recent studies the event GW190521 has been suggested to be a capture event. With this interpretation of GW190521, we find the merger rate of similar events to be $0.47{\mathrm{Gpc}}^{-3}{\mathrm{yr}}^{-1}$.

The waveforms from binary black hole mergers include inspiral, merger, and ringdown parts. Usually, the inspiral waveform can be obtained by calibrating from post-Newtonian approximation; The merger and ringdown ones can be gotten from the quasinormal modes with black hole perturbation theory. However, for more general black holes, the calculation of the quasinormal modes is not trivial. In this paper we use the photon sphere to get the quasinormal modes of spinning black holes. Then we connect the ringdown wave with the inspiral part to get full waveforms and compare with the ones from numerical relativity. We find that they match with each other very well. In principle this method can be extended to some general compact objects. As an example, the ringdown waveforms from parametrized axisymmetric black holes are obtained. We also use this method to get the ringdown signals of the accelerating final black hole; this is due to gravitational recoil during the merger. Even for the extreme cases, the acceleration due to the recoil cannot produce detectable effects.

Recently anomalous flux in the cosmic optical background (COB) is reported by the New Horizon observations. The COB flux is $16.37\pm 1.47\mathrm{n}{\mathrm{Wm}}^{-2}{\mathrm{sr}}^{-1}$, at the LORRI pivot wavelength of $0.608\mathrm{\mu }\mathrm{m}$, which is $\sim 4\sigma$ level above the expected flux from the Hubble Space Telescope (HST) galaxy count. It would be great if this were a hint for the eV scale dark matter decaying into photons. In this paper, we point out that such a decaying dark matter model predicts a substantial amount of anisotropy in the COB flux, which is accurately measured by the HST. The data of the HST excludes the decay rate of the dominant cold dark matter larger than ${10}^{-24}–{10}^{-23}{\mathrm{s}}^{-1}$ in the mass range of 5–20 eV. As a result, the decaying cold dark matter explaining the COB excess is strongly disfavored by the anisotropy bound. We discuss some loopholes: e.g., warm/hot dark matter or two-step decay of the dark matter to explain the COB excess.

Nova outbursts take place in binary star systems comprising a white dwarf and either a low-mass Sun-like star (classical novae) or, a red giant. GeV gamma-ray emission has been detected from a dozen classical novae and from one nova in a symbiotic system (V407 Cyg) by Fermi-LAT. For classical novae, gamma-ray emission is generally thought to be related to internal shocks formed as fast outflow collides with the slow outflow. However, for V407 Cyg, the origin of the gamma-ray emission has been debated, as both an internal shock and an external shock resulting from the collision between the nova ejecta and the ambient wind of the giant companion, and were suggested to explain the gamma-ray data. Recently, bright GeV and TeV gamma-ray emission has been detected from a nova in symbiotic system, RS Ophiuchi, during its 2021 outburst, which shows a remarkably smooth power-law decay in time up to about one month after the outburst. We show that this temporal decay behavior can be interpreted as arising from an adiabatic external shock expanding in the red giant wind. In this interpretation, the gamma rays are produced by shock-accelerated protons interacting with the dense wind through the hadronic process. We also derive the scaling relations for the decay slopes for both adiabatic and radiative nova shocks in the self-similar deceleration phase.

Dark matter makes up 85% of the matter in the Universe and 27% of its energy density, but we do not know what comprises dark matter. It is possible that dark matter is composed of either axions or dark photons, both of which can be detected using an ultrasensitive microwave cavity known as a haloscope. The haloscope employed by ADMX consists of a cylindrical cavity operating at the ${\mathrm{TM}}_{010}$ mode and is sensitive to the QCD axion with masses of few $\mu \mathrm{eV}$. However, this haloscope design becomes challenging to implement for higher masses. This is because higher masses require smaller-diameter cavities, consequently reducing the detection volume which diminishes the detected signal power. ADMX-Orpheus mitigates this issue by operating a tunable, dielectrically loaded cavity at a higher-order mode, allowing the detection volume to remain large. This paper describes the design, operation, analysis, and results of the inaugural ADMX-Orpheus dark photon search between $65.5\mu \mathrm{eV}$ (15.8 GHz) and $69.3\mu \mathrm{eV}$ (16.8 GHz), as well as future directions for axion searches and for exploring more parameter space.

Unsupervised training of generative models is a machine learning task that has many applications in scientific computing. In this work we evaluate the efficacy of using quantum circuit-based generative models to generate synthetic data of high energy physics processes. We use nonadversarial, gradient-based training of quantum circuit Born machines to generate joint distributions over two and three variables.

We calculate the mass spectrum of the $S$-wave fully-charmed tetraquark resonant states $cc\overline{c}\overline{c}$ in the nonrelativistic quark model, which successfully describes the charmonium spectrum. The four-body system is solved with the Gaussian expansion method. The complex scaling technique is used to identify the genuine resonances. With the nonrelativistic quark model, our results show the existence of two $cc\overline{c}\overline{c}$ resonances in each of the $J^{PC}=0^{++}$, $1^{+-}$, and $2^{++}$ sectors, respectively. In the $S$-wave sector, no resonance is found at the energy region of the $X(6200)$ and $X(6600)$ states. The lower $0^{++}$ and $2^{++}$ resonances are located around 100 MeV higher than the $X(6900)$ state observed in experiments but have the decay widths consistent with the experiment. The higher $0^{++}$ and $2^{++}$ resonances are found at around 7.2 GeV with the widths of 60.6 MeV and 91.2 MeV, respectively, and they may be good candidates for the $X(7200)$ state.

In this paper, we point out a novel signature of physics beyond the Standard Model which could potentially be observed both at the Large Hadron Collider (LHC) and at future colliders. This signature, which emerges naturally within many proposed extensions of the Standard Model, results from the multiple displaced vertices associated with the successive decays of unstable, long-lived particles along the same decay chain. We call such a sequence of displaced vertices a “tumbler.” We examine the prospects for observing tumblers at the LHC and assess the extent to which tumbler signatures can be distinguished from other signatures of new physics which also involve multiple displaced vertices within the same collider event. As part of this analysis, we also develop a procedure for reconstructing the masses and lifetimes of the particles involved in the corresponding decay chains. We find that the prospects for discovering and distinguishing tumblers can be greatly enhanced by exploiting precision timing information such as would be provided by the CMS timing layer at the high-luminosity LHC. Our analysis therefore provides strong additional motivation for continued efforts to improve the timing capabilities of collider detectors at the LHC and beyond.

We consider a dark confining gauge theory with millicharged ultralight pions (ULP) and heavy baryons as dark matter candidates. The model simultaneously realizes the ultralight (strongly interacting ultralight millicharged particle or “STUMP”) and superheavy (“WIMPzilla”) dark matter paradigms, connected by the confinement scale of the dark QCD. It is a realization of millicharged ultralight dark matter, unlike conventional axions, and exhibits a mass splitting between the charged and neutral pions. ULPs can easily provide the observed density of the dark matter, and be cosmologically stable, for a broad range of dark QCD scales and quark masses. The dark baryons, produced via gravitational particle production or via freeze-in, provide an additional contribution to the dark matter density. Dark matter halos and boson stars in this context are generically an admixture of the three pions and heavy baryons, leading to a diversity of density profiles. That opens up the accessible parameter space of the model compared with the standard millicharged dark matter scenarios and can be probed by future experiments. We briefly discuss additional interesting phenomenology, such as ULP electrodynamics, and cosmic ULP backgrounds.

The first-order nature of the chiral phase transition in QCD-like theories can play crucial roles in addressing a dark side of the Universe, where the created out-of equilibrium is essential to serve as cosmological and astrophysical probes such as gravitational wave productions, which have extensively been explored. This interdisciplinary physics is built based on a widely accepted conjecture that the thermal chiral phase transition in QCD-like theories with massless (light) three flavors is of first order. We find that such a first order feature may not hold when ordinary or dark quarks are externally coupled to a weak enough background field of photon or dark photon (which we collectively call a “magnetic” field). We assume that a weak magnetic background field could be originated from some “magnetogenesis” in the early Universe. We work on a Nambu-Jona-Lasinio model which can describe the chiral phase transition in a wide class of QCD-like theories. We show that in the case with massless (light) three flavors, the first-order feature goes away when $2f_{\pi }^2\lesssim eB(\ll (4\pi f_{\pi }{)}^2)$, where $eB$ is the magnetic field strength and $f_{\pi }$ the pion decay constant at the vacuum. This disappearance is the generic consequence of the presence of the “magnetically” induced scale anomaly and the magnetic catalysis for the chiral symmetry breaking, and would impact or constrain modeling dark QCD coupled to an external magnetic field.

We calculate the contribution from the $q\overline{q}g$ state production to the diffractive cross sections in deep inelastic scattering at high energy. The obtained cross section is finite by itself and a part of the full next-to-leading order result for the diffractive structure functions. We perform the calculation in exact kinematics in the eikonal limit, and show that the previously known high-$Q^2$ and large $M_X^2$ results for the structure functions can be extracted from our results in the appropriate limits. We furthermore discuss the steps required to obtain the full next-to-leading order results for the structure functions.

We perform the first global and unitary analysis of $e^{+}{e}^{-}\to b\overline{b}$ cross sections. We analyze exclusive cross sections in the $B\overline{B}$, $B^{*}\overline{B}(+\mathrm{c}.\mathrm{c}.)$, $B^{*}{\overline{B}}^{*}$, $B_s^{*}{\overline{B}}_s^{*}$, $\mathrm{\Upsilon }(nS){\pi }^{+}{\pi }^{-}$, and $h_b(nP){\pi }^{+}{\pi }^{-}$ channels as well as the total inclusive cross section for $b\overline{b}$ production. Pole positions and residues are determined for four vector states, which we associate with the $\mathrm{\Upsilon }(4S)$, $\mathrm{\Upsilon }(10750)$, $\mathrm{\Upsilon }(5S)$ [or $\mathrm{\Upsilon }(10860)$], and $\mathrm{\Upsilon }(6S)$ [or $\mathrm{\Upsilon }(11020)$]. We find strong evidence for the new $\mathrm{\Upsilon }(10750)$ recently claimed by Belle, although with parameters not well constrained by the data. Results presented here cast doubt on the validity of branching ratios reported earlier using Breit-Wigner parametrizations or ratios of cross sections. We also compare our results with a selection of theoretical calculations for the vector-bottomonium spectrum.

Recently, the BABAR Collaboration reported a broad resonance structure near 2 GeV when analyzing the $e^{+}{e}^{-}\to f_1(1285){\pi }^{+}{\pi }^{-}$ process, which provides a good opportunity to study the higher $\rho$-mesonic states. When considering the $\rho (1900)$ and $\rho (2150)$ contributions, the experimental data of the cross section of $e^{+}{e}^{-}\to f_1(1285){\pi }^{+}{\pi }^{-}$ around 2 GeV can be well depicted, especially the observed broad resonance structure in $e^{+}{e}^{-}\to f_1(1285){\pi }^{+}{\pi }^{-}$ containing two substructures is suggested by the present work. Additionally, we also indicate a possible signal of $\rho (5S)$ around 2.5 GeV in the $e^{+}{e}^{-}\to f_1(1285){\pi }^{+}{\pi }^{-}$ process. The obtained result may provide a valuable hint to identify higher $\rho$ mesons, which will be a new task for the BESIII and Belle II experiments with the accumulation of higher precision data.