Neutrino cross section and oscillation measurements depend critically on modeling of hadronic final state interactions (FSI). Often, this is one of the largest components of uncertainty in a measurement. This is because of the difficulty in modeling strong interactions in nuclei in a consistent quantum-mechanical framework. FSI models are most often validated using hadron-nucleus data which introduces further uncertainties. The alternative is to use transparency data where the hadron starts propagating from inside the nucleus and the probability of interaction is measured as a function of hadron energy. This work examines the relationship between the ${\pi }^{+}$ and proton total reaction cross section and transparency from a simulation viewpoint.

Studies of $CP$ violation and anomalous couplings of the Higgs boson to vector bosons and fermions are presented. The data were acquired by the CMS experiment at the LHC and correspond to an integrated luminosity of $137{\mathrm{fb}}^{-1}$ at a proton-proton collision energy of 13 TeV. The kinematic effects in the Higgs boson’s four-lepton decay $H\to 4\ell$ and its production in association with two jets, a vector boson, or top quarks are analyzed, using a full detector simulation and matrix element techniques to identify the production mechanisms and to increase sensitivity to the tensor structure of the Higgs boson interactions. A simultaneous measurement is performed of up to five Higgs boson couplings to electroweak vector bosons ($HVV$), two couplings to gluons ($Hgg$), and two couplings to top quarks ($Htt$). The $CP$ measurement in the $Htt$ interaction is combined with the recent measurement in the $H\to \gamma \gamma$ channel. The results are presented in the framework of anomalous couplings and are also interpreted in the framework of effective field theory, including the first study of $CP$ properties of the $Htt$ and effective $Hgg$ couplings from a simultaneous analysis of the gluon fusion and top-associated processes. The results are consistent with the standard model of particle physics.

Using the $\mathrm{AdS}/\mathrm{CFT}$ correspondence we consider the retarded Green’s function in the background of rotating near-extremal anti–de Sitter ${(\mathrm{AdS})}_4$ black holes. Following the canonical $\mathrm{AdS}/\mathrm{CFT}$ dictionary into the asymptotic boundary we get a conformal field theory ${(\mathrm{CFT})}_3$ result. We also take a new route and zoom in on the near-horizon region, blow up this region and show that it yields a ${\mathrm{CFT}}_2$ result. We argue that the decoupling of the near-horizon region is akin to the decoupling of the near-throat region of a D3-brane, which led to the original formulation of the $\mathrm{AdS}/\mathrm{CFT}$ correspondence, thus implying that the Kerr/CFT correspondence follows as a decoupling of the standard $\mathrm{AdS}/\mathrm{CFT}$ correspondence applied to rotating black holes. As a byproduct, we compute the shear viscosity to entropy density ratio for the strongly coupled boundary ${\mathrm{CFT}}_3$, and find that it violates the $1/(4\pi )$ bound.

Gravity and matter are universally coupled, and this unique universality provides us with an intriguing way to quantify quantum aspects of space-time in terms of the number of gravitons within a given box. In particular, we provide a limit on the number of gravitons if we trace out the matter degrees of freedom. We obtain the universal bound on the number of gravitons, which would be given by $N_g\approx (m/M_p{)}^2$. Since the number of gravitons also signifies the number of bosonic states they occupy, the number of gravitons indirectly constrain the system’s gravitational entropy. We show that it saturates the Bekenstein bound on the gravitational area law of entropy. Based on these observations, we ascertain that the gravitons permeating in the observable Universe are always $N_g\gg 1$.

We describe a simple model for quantum interference of a single photon in the Mach-Zehnder interferometer using the Heisenberg picture. Our purpose is to show that the description in the Heisenberg picture is local just like in the case of the classical electromagnetic field, the only difference being that the electric and the magnetic fields are, in the quantum case, operators representing quantum observables. We then consider a simple model for a single-electron Mach-Zehnder interferometer and explain what the appropriate Heisenberg picture treatment is in this case. Interestingly, the parity superselection rule that arises in fermions due to the different spin statistics forces us to describe the electron in a radically different way to the photon in order to preserve the account in terms of local observables. A model using only local quantum observables of fermionic modes (such as the current operator) is nevertheless still viable to describe phase acquisition. We discuss how to extend this local analysis to coupled fermionic and bosonic fields within the same local formalism of quantum electrodynamics as formulated in the Heisenberg picture.

Accurate extractions of the detected gravitational wave (GW) signal waveforms are essential to validate a detection and to probe the astrophysics behind the sources producing the GWs. This however could be difficult in realistic scenarios where the signals detected by existing GW detectors could be contaminated with nonstationary and non-Gaussian noise. While the performance of existing waveform extraction methods are optimal, they are not fast enough for online application, which is important for multimessenger astronomy. In this paper, we demonstrate that a deep learning architecture consisting of convolutional neural network and bidirectional long short-term memory components can be used to extract binary black hole (BBH) GW waveforms from realistic noise in a few milliseconds. We have tested our network systematically on injected GW signals, with component masses uniformly distributed in the range of 10 to $80M_{\odot }$, on Gaussian noise and Laser Interferometer Gravitational Wave Observatory (LIGO) detector noise. We find that our model can extract GW waveforms with overlaps of more than 0.95 with pure numerical relativity templates for signals with signal-to-noise ratio greater than six and is also robust against interfering “glitches”. We then apply our model to all ten detected BBH events from LIGO-Virgo’s first (O1) and second (O2) observation runs, obtaining $\ge 0.97$ overlaps for all ten extracted BBH waveforms with the corresponding pure templates. We discuss the implication of our result and its future applications to GW localization and mass estimation.

The aim of this paper is to study the stability of solitonlike static solutions via nonlinear simulations in the context of a special class of massive tensor-multiscalar theories of gravity whose target space metric admits Killing field(s) with a periodic flow. We focused on the case with two scalar fields and maximally symmetric target space metric, as the simplest configuration where solitonic solutions can exist. In the limit of zero curvature of the target space $\kappa =0$ these solutions reduce to the standard boson stars, while for $\kappa \ne 0$ significant deviations can be observed; both qualitative and quantitative. By evolving these solitonic solutions in time, we show that they are stable for low values of the central scalar field ${\psi }_c$ while instability kicks in with the increase of ${\psi }_c$. As expected from the study of the equilibrium models, the change of stability occurs exactly at the maximum mass point, which was checked numerically with a very good accuracy. Moreover, different scenarios for unstable solutions—i.e., collapse or expansion of unstable initial configurations—have been investigated by assuming different perturbations around equilibrium.

In this paper, we have investigated a bulk viscous universe with dominance of dark energy in Bianchi type I space-time and constrained its parameter with observational $H(z)$ data (OHD) and joint OHD and Pantheon compilation of SN Ia data. We constrain Hubble’s constant $H_0=69.38_{-1.54}^{+1.57}$ and $H_0=70.017_{-1.60}^{+1.62}\mathrm{km}{\mathrm{s}}^{-1}{\mathrm{Mpc}}^{-1}$ by bounding this model with OHD and joint OHD and Pantheon compilation of SN Ia data respectively. These estimated values of $H_0$ have $1.27\sigma$ and $1.69\sigma$ tension with its corresponding Planck collaboration value. We have constrained the best fit value of model parameter $\zeta$ as $\zeta =0.000027_{-0.00052}^{+0.00052}$ and $\zeta =0.000033_{-0.00296}^{+0.00296}$ respectively for the above observational datasets. We also have obtained a kinematic expression for deceleration parameter and constrained its present value $q_0=-0.582_{-0.023}^{+0.021}$ and transition redshift $z_t=0.723_{-0.16}^{+0.34}$. Furthermore, we observe that the derived model exhibits the properties of transitioning the universe and its present age is $t_0=14.04_{-0.32}^{+0.33}\mathrm{Gyrs}$. The kinematics of the Om(z) parameter and the jerk parameter are also discussed and the analysis of these parameters shows a marginal departure of the derived model from the $\mathrm{\Lambda }\mathrm{CDM}$ model of the universe.

We study models with several $SU(2)$ scalar doublets where the inert doublets have a nonminimal coupling to gravity and play the role of the inflaton. We allow for this coupling to be complex, thereby introducing $CP$ violation—a necessary source of the baryon asymmetry—in the Higgs-inflaton couplings. We investigate the inflationary dynamics of the model and discuss how the $CP$ violation of the model is imprinted on the particle asymmetries after inflation in the hot big bang universe.

We theoretically and observationally investigate different choices of initial conditions for the primordial mode function that are imposed during an epoch preceding inflation. By deriving predictions for the observables resulting from several alternate quantum vacuum prescriptions we show some choices of vacua are theoretically observationally distinguishable from others. Comparing these predictions to the Planck 2018 observations via a Bayesian analysis shows no significant evidence to favor any of the quantum vacuum prescriptions over the others. In addition we consider frozen initial conditions, representing a white-noise initial state at the big-bang singularity. Under certain assumptions the cosmological concordance model and frozen initial conditions are found to produce identical predictions for the cosmic microwave background anisotropies. Frozen initial conditions may thus provide an alternative theoretic paradigm to explain observations that were previously understood in terms of the inflation of a quantum vacuum.

We show that relic vector fields can significantly impact a spectrum of primordial gravitational waves in the postinflationary era. We consider a triplet of U(1) fields in a homogeneous, isotropic configuration. The interaction between the gravitational waves and the vector fields, from the end of reheating to the present day, yields novel spectral features. The amplitude, tilt, shape, and net chirality of the gravitational wave spectrum are shown to depend on the abundance of the electric- and magneticlike vector fields. Our results show that even a modest abundance can have strong implications for efforts to detect the imprint of gravitational waves on the cosmic microwave background polarization. We find that a vector field comprising less than 2% of the energy density during the radiation-dominated era can have a greater than order unity effect on the predicted inflationary gravitational wave spectrum.

We introduce a new technique to search for gravitational wave events from compact binary mergers that produce a clear signal only in a single gravitational wave detector, and marginal signals in other detectors. Such a situation can arise when the detectors in a network have different sensitivities, or when sources have unfavorable sky locations or orientations. We start with a short list of loud single-detector triggers from regions of parameter space that are empirically unaffected by glitches (after applying signal-quality vetoes). For each of these triggers, we compute evidence for astrophysical origin from the rest of the detector network by coherently combining the likelihoods from all detectors and marginalizing over extrinsic geometric parameters. We report the discovery of two new binary black hole (BBH) mergers in the second observing run of Advanced LIGO and Virgo (O2), in addition to the ones that were reported in [B. P. Abbott et al. (LIGO Scientific and Virgo Collaborations), Phys. Rev. X 9, 031040 (2019) and [T. Venumadhav et al., Phys. Rev. D 101, 083030 (2020)]. We estimate that the two events have false alarm rates of one in 19 years (60 O2) and one in 11 years (36 O2). One of the events, GW170817A, has primary and secondary masses $m_1^{\mathrm{src}}=56_{-10}^{+16}{M}_{\odot }$ and $m_2^{\mathrm{src}}=40_{-11}^{+10}{M}_{\odot }$ in the source frame. The existence of GW170817A should be very informative about the theoretically predicted upper mass gap for stellar mass black holes. Its effective spin parameter is measured to be ${\chi }_{\mathrm{eff}}=0.5\pm 0.2$, which is consistent with the tendency of the heavier detected BBH systems to have large and positive effective spin parameters. The other event, GWC170402, will be discussed thoroughly in future work.

Future experiments based on the observation of Earth’s atmosphere from sub-orbital and orbital altitudes plan to include optical Cherenkov cameras to observe extensive air showers produced by high-energy cosmic radiation via its interaction with both the Earth and its atmosphere. As discussed elsewhere [Phys. Rev. D 103, 043017 (2021); Phys. Rev. D 100, 063010 (2019)], particularly relevant is the case of upward-moving showers initiated by astrophysical neutrinos skimming and interacting in the Earth. The Cherenkov cameras, by looking above Earth’s limb, can also detect cosmic rays with energies starting from less than a PeV up to the highest energies (tens of EeV). Using a customized computation scheme to determine the expected optical Cherenkov signal from these high-energy cosmic rays, we estimate the sensitivity and event rate for balloon-borne and satellite-based instruments, focusing our analysis on the Extreme Universe Space Observatory aboard a Super Pressure Balloon 2 (EUSO-SPB2) and the Probe of Extreme Multi-Messenger Astrophysics (POEMMA) experiments. We find the expected event rates to be larger than hundreds of events per hour of experimental live time, enabling a promising overall test of the Cherenkov detection technique from sub-orbital and orbital altitudes as well as a guaranteed signal that can be used for understanding the response of the instruments.

We put constraints on the secondary component of GW190814 by analyzing the observational data of the event. The relativistic mean-field models are used to calculate the mass-radius profile and tidal deformability of the compact object, considering it as a massive neutron star with the presence of dark matter particles inside it. With the increase of dark matter percentage, the maximum mass, radius, and tidal deformability of the neutron star decreases. We observe that the predicted properties are well consistent with GW190814 observational data, suggesting the possibility of a dark matter admixed neutron star if the underlying nuclear equation of state is sufficiently stiff.

Axion is a promising candidate for ultralight dark matter which may cause a polarization rotation of laser light. Recently, a new idea of probing the axion dark matter by optical linear cavities used in the arms of gravitational wave detectors has been proposed [Phys. Rev. Lett. 123, 111301 (2019). In this article, a realistic scheme of the axion dark matter search with the arm cavity transmission ports is revisited. Since photons detected by the transmission ports travel in the cavity for odd-number of times, the effect of axion dark matter on their phases is not canceled out and the sensitivity at low-mass range is significantly improved compared to the search using reflection ports. We also take into account the stochastic nature of the axion field and the availability of the two detection ports in the gravitational wave detectors. The sensitivity to the axion-photon coupling, $g_{a\gamma }$, of the ground-based gravitational wave detector, such as Advanced LIGO, with 1-year observation is estimated to be $g_{a\gamma }\sim 3\times {10}^{-12}{\mathrm{GeV}}^{-1}$ below the axion mass of ${10}^{-15}\mathrm{eV}$, which improves upon the limit achieved by the CERN Axion Solar Telescope.

We present a method to extract the phase shift of a scattering process using the real-time evolution in the early and intermediate stages of the collision in order to estimate the time delay of a wave packet. This procedure is convenient when using noisy quantum computers for which the asymptotic out-state behavior is unreachable. We demonstrate that the challenging Fourier transforms involved in the state preparation and measurements can be implemented in $1+1$ dimensions with current trapped ion devices and IBM quantum computers. We compare quantum computations of the time delays obtained in the one-particle quantum mechanics limit and the scalable quantum field theory formulation with accurate numerical results. We discuss the finite volume effects in the Wigner formula connecting time delays to phase shifts. The results reported involve two- and four-qubit calculations, and we discuss the possibility of larger scale computations in the near future.

A modification of the one boson exchange (OBE) kernel for the covariant spectator theory (CST) is presented and discussed. When applied to the scattering of two identical particles, the previously used kernels either introduced spurious singularities, or removed them in an ad-hoc way. The new modification not only removes these singularities, but also maintains the convergence of the two-body CST equation (sometimes called the Gross equation) when used to describe the scattering of two identical scalar particles.

In the present paper, we check and study the validity of the KATIE parton level event generator by calculating the inclusive electron-proton (ep) dijet and the proton-proton (pp) Drell-Yan electron-pair production’s differential cross sections in the $k_t$- and collinear factorization frameworks. The Martin-Ryskin-Watt (MRW) unintegrated parton distribution functions (UPDFs) are used as the input UPDFs. The results are compared with those of ZEUS ep inclusive dijet and ATLAS p-p Drell-Yan electron-pair productions, experimental data. The KATIE parton level event generator can directly calculate the cross sections in the $k_t$-factorization framework. It was noticed by van Hameren, the author of KATIE, that the lab to the Breit transformation in this generator was not correctly implemented, so the produced output did not cover the ep ZEUS experimental data in which the mentioned transformation is applied. The author of the code fixed the bug by implementing the correct transformation in the KATIE parton event generator. Then, we could appropriately produce the ep inclusive dijet differential cross section, in comparison with those of ZEUS data. It is also shown that the Martin-Ryskin-Watt at the next-to-leading order level, with the angular ordering constraint, can successfully predict the ATLAS p-p Drell-Yan data. Finally, as it is expected, we conclude that the $k_t$ factorization is an appropriate tool for the small longitudinal parton momenta and high center of mass energies, with respect to the collinear one.