Exponential resummation of the QCD finite-density Taylor series has been recently introduced as an alternative way of resumming the finite-density lattice QCD Taylor series. Unfortunately the usual exponential resummation formula suffers from stochastic bias which must be subtracted before identifying genuine higher-order contributions. In this paper, we present a new way of subtracting the stochastic bias at the level of each individual gauge configuration, up to a certain order of either the Taylor series or the cumulant expansion, by modifying the argument of the exponential. Retaining the exponential form of the resummation allows us to also calculate the phase factor of the fermion determinant on each gauge configuration. We present our results for the excess pressure, number density, and the average phase factor and show that the new results contain less stochastic bias and are in better agreement with the QCD Taylor series compared to the previous exponential resummation.

The elastic pion-proton and pion-pion scattering are studied in a holographic QCD model, focusing on the Regge regime. Taking into account the Pomeron and Reggeon exchange, which are described by the Reggeized $2^{++}$ glueball and vector meson propagator respectively, the total and differential cross sections are calculated. The adjustable parameters involved in the model are determined with the experimental data of the pion-proton total cross sections. The differential cross sections can be predicted without any additional parameters, and it is shown that our predictions are consistent with the data. The energy dependence of the Pomeron and Reggeon contribution is also discussed.

An extended Roy equation including a bound state pole is used to study $\pi \pi$ scatterings at unphysical large pion masses when $\sigma$ becomes a bound state in one situation and stays as a broad resonance in the other case. The coupled integral equations at large pion masses are solved by taking the lattice driving terms and the Regge amplitudes as inputs. Relying on the solutions of Roy equations that respect unitarity, analyticity and crossing symmetry, we give predictions to the phase shifts with $IJ=00$, 11, 20 in the elastic energy region. We then perform analytic continuation into the complex $s$ plane to search for various poles, all of which are inside the validity domain of the Roy equation. This is the first time that lattice data at unphysical large pion masses are analyzed within the rigorous Roy equation method.

We study two (massless free field) models, a photon/photino model with a vector gauge field and a Majorana spinor field, and a Wess-Zumino model. They each exhibit Lorentz symmetry violation but retain, in an appropriate way, the supersymmetry correspondence between the particles of the two fields. In relation to the photon field the Lorentz symmetry violation is of a simple but nontrivial kind that implies birefringence. In relation to the spinor field the Lorentz violation is produced by a modification of the Majorana equation that is a simplified version of more general investigations of Lorentz symmetry violation of the Dirac equation. In the case of the Wess-Zumino model we retain the same violation of Lorentz symmetry for the Majorana field and adjust the propagation of the scalar particles so that they exhibit a corresponding birefringence. The advantages of the models are that they are straightforward to investigate completely and both retain the basic aspect of supersymmetry namely the one-to-one correspondance between bosons and fermions. As a result of this bottom-up approach it is then possible to construct conserved supersymmetry charges and investigate their algebraic properties. To some extent these are similar to those encountered in the case of Lorentz invariance. However, there are differences and in particular nonlocal terms appear in the commutation relations of the supersymmetry charges and fields of the models. We examine carefully the rather intricate nature of the limit back to Lorentz invariance.

This study explores the properties of black holes and scalarons in Einstein gravity when it is minimally coupled to a scalar field $\varphi$ with an asymmetric potential $V(\varphi )$, constructed in [A. Corichi et al., Phys. Rev. D 73, 084002 (2006)] a few decades ago. $V(\varphi )$ has been applied in cosmology to describe the quantum tunneling process from the false vacuum to the true vacuum and contains a local maximum, a local minimum (false vacuum), and a global minimum (true vacuum). We focus on the asymptotically flat solutions, which can be constructed by appropriately fixing the local minimum of $V$. A branch of hairy black hole solutions emerges from the Schwarzschild black hole, and we study the domain of existence of such configurations. They can reach to a particlelike solution in the small horizon limit, i.e., the scalarons. We study the stability of black holes and scalarons, showing that all are unstable under radial perturbations.

Einstein-Dirac-Maxwell wormholes are asymptotically flat static wormhole solutions in general relativity that do not make use of exotic matter. The asymmetric static solutions are smooth, are regular everywhere, and violate the null energy condition, which suggests that they are traversable. To determine if, in fact, they are traversable, we numerically evolve the static solutions forward in time. In all cases considered, our simulations indicate that black holes form that are connected by the wormhole. Although there exist null geodesics that travel through the wormhole, we find that they are trapped inside a black hole and are unable to travel arbitrarily far away. We conclude that Einstein-Dirac-Maxwell wormholes are not traversable.

Although the hybrid natural inflation is a successful inflation model, the symmetry breaking scale in the model should be large for a negative value of the running of the scalar spectral index. This study proposed a generalized hybrid natural inflation model that can realize a low-scale inflation with a negative value of the running of the scalar spectral index.

In this work, a modified two-flavor Nambu-Jona–Lasinio-type model is utilized, in which the contact current-current interaction is Fierz-transformed into quark-antiquark interactions and quark-quark interactions, which are directly related to the chiral condensate and diquark condensate, respectively. Under mean-field approximation, the chiral condensate and the diquark condensate are studied on the same footing. We discuss in detail the competition between the chiral condensate and the diquark condensate, which are exclusively paired with u and d quarks, while also investigating the order of the chiral phase transition through an analysis of the resulting chiral susceptibility.

We identify a geometric symmetry on the two-flavor Bloch sphere for collective flavor oscillations of a homogeneous dense neutrino gas. Based on this symmetry, analytical solutions to the periodic bipolar flavor evolution are derived. Using numerical calculations, we show that for configurations without this symmetry, the flavor evolution displays deviations from the bipolar flavor motion or even exhibits aperiodic patterns. We also discuss the implication of our finding for more general three-flavor and inhomogeneous cases.

In this work we calculate the decay widths of $\varphi (2170)$ to $\varphi \eta$ and $\varphi {\eta }^{\prime }$ by considering $\varphi (2170)$ as a $\varphi K\overline{K}$ state, with $K\overline{K}$ clustering as $f_0(980)$. These decay widths have been recently determined by the BESIII, BABAR, and Belle collaborations with the aim of unraveling the nature of $\varphi (2170)$. By analyzing the data on the cross sections of the process $e^{+}{e}^{-}\to \varphi \eta$, two solutions were found by the BESIII collaboration with the same ${\chi }^2$ per number of degrees of freedom (n.d.f.), mass and width for $\varphi (2170)$. However, different values for ${\mathcal{B}}_{\varphi \eta }^{\varphi (2170)}{\mathrm{\Gamma }}_{e^{+}{e}^{-}}^{\varphi (2170)}$ were obtained, where ${\mathcal{B}}_{\varphi \eta }^{\varphi (2170)}$ is the branching fraction of $\varphi (2170)\to \varphi \eta$ and ${\mathrm{\Gamma }}_{e^{+}{e}^{-}}^{\varphi (2170)}$ is the decay width for $\varphi (2170)\to e^{+}{e}^{-}$: ${0.24}_{-0.07}^{+0.12}\mathrm{eV}$ (solution I) and ${10.11}_{-3.13}^{+3.87}\mathrm{eV}$ (solution II). In case of ${\mathcal{B}}_{\varphi {\eta }^{\prime }}^{\varphi (2170)}{\mathrm{\Gamma }}_{e^{+}{e}^{-}}^{\varphi (2170)}$, a value of $7.1\pm 0.7\pm 0.7$ was determined by the BESIII collaboration from fits to the data on the cross section of $e^{+}{e}^{-}\to \varphi {\eta }^{\prime }$. The Belle collaboration has also determined ${\mathcal{B}}_{\varphi \eta }^{\varphi (2170)}{\mathrm{\Gamma }}_{e^{+}{e}^{-}}^{\varphi (2170)}$ more recently, although the statistical significance related to the signal of $\varphi (2170)$ in the data is low. We calculate the decay widths of $\varphi (2170)$ to $\varphi \eta$ and $\varphi {\eta }^{\prime }$, and compare their ratio ${\mathrm{\Gamma }}_{\varphi \eta }^{\varphi (2170)}/{\mathrm{\Gamma }}_{\varphi {\eta }^{\prime }}^{\varphi (2170)}$ with the one determined by using the above mentioned experimental data. Considering the theoretical and experimental uncertainties, the lower limit of our theoretical result ($\simeq 2.6$) is close to the upper value obtained ($\simeq 2$) by using the solution II of BESIII for ${\mathcal{B}}_{\varphi \eta }^{\varphi (2170)}{\mathrm{\Gamma }}_{e^{+}{e}^{-}}^{\varphi (2170)}$, as well as to the upper limit found ($\simeq 2.8$) when considering the solutions III and IV of the Belle collaboration for ${\mathcal{B}}_{\varphi \eta }^{\varphi (2170)}{\mathrm{\Gamma }}_{e^{+}{e}^{-}}^{\varphi (2170)}$.

Under the basis light-front quantization framework, we investigate the leading-twist transverse-momentum-dependent parton distribution functions (TMDs) for $\mathrm{\Lambda }$ and ${\mathrm{\Lambda }}_c$ baryons, the spin-$1/2$ composite systems consisting of two light quarks ($u$ and $d$) and a $s/c$ quark. We evaluate the TMDs using the overlaps of the light-front wave functions in the leading Fock sector, which are obtained by solving the light-front eigenvalue equation. We also study the spin densities of quarks in momentum space for various polarizations. In the same model, we compare the TMDs of the strange and charmed baryons and the proton by reviewing their spin structures in the quark model and the probabilistic interpretations of their TMDs.

In this work, the neutral Higgs boson pair production is analyzed at the Compact Linear Collider (CLIC) to be operating at center of mass energies $\sqrt{s}=1400\mathrm{GeV}$ (stage 2) and $\sqrt{s}=3000\mathrm{GeV}$ (stage 3). The Higgs bosons to be searched for are neutral $CP$ even ($H$) and $CP$ odd ($A$) within the framework of two Higgs doublet model (2HDM) in the mass range $300<m_{H/A}<1000\mathrm{GeV}$. All types of $CP$-conserving models are studied and the signal observability is evaluated, taking into account the main SM background processes like $ZZ$, $t\overline{t}$, and the SM-like Higgs boson associated production ($hZ$). Results are presented for a set of model parameters and Higgs boson masses in terms of signal distributions over the background as well as the integrated luminosity needed for $5\sigma$ discovery. It is shown that the heavy mass region is well observable at CLIC in types 3 and 4 in the regions not excluded by LHC so far, while in type 1 the signal observation is challenging due to the large jet multiplicity in the $t\overline{t}$ final state.

Boosted top quark tagging is one of the challenging, and at the same time exciting, tasks in high energy physics experiments, in particular in the exploration of new physics signals at the LHC. Several techniques have already been developed to tag a boosted top quark in its hadronic decay channel. Recently tagging the same in the semileptonic channel has begun to receive a lot of attention. In the current study, we develop a methodology to tag a boosted top quark ($p_T>200\mathrm{GeV}$) in its semileptonic decay channel with a $\tau$-lepton in the final state. In this analysis, the constituents of the top fatjet are reclustered using jet substructure technique to obtain the subjets, and then $b$- and $\tau$- like subjets are identified by applying standard $b$- and $\tau$-jet identification algorithms. We show that the dominant QCD background can be rejected effectively using several kinematic variables of these subjects, such as energy sharing among the jets, invariant mass, transverse mass, $N$-subjettiness etc., leading to high signal tagging efficiencies. We further assess possible improvements in the results by employing multivariate analysis techniques. We find that using this proposed top-tagger, a signal efficiency of $\sim 77\%$ against a background efficiency of $\sim 3\%$ can be achieved. We also extend the proposed top-tagger to the case of polarized top quarks by introducing a few additional observables calculated in the rest frame of the $b-\tau$ system. We comment on how the same methodology will be useful for tagging a boosted heavy BSM particle with a $b$ and $\tau$ in the final state.

It remains a possibility that neutrinos are pseudo-Dirac states, such that a generation is composed of two maximally mixed Majorana neutrinos separated by a very small mass difference. We explore the physics potential of the JUNO experiment in constraining this possibility using the measurement of solar neutrinos. In particular, we investigate cases where one or three sterile states are present in addition to the active states. We consider two scenarios: one where JUNO’s energy threshold allows for the measurement of $pp$ solar neutrinos, and the case where JUNO can only measure ${}^7\mathrm{Be}$ neutrinos and above. We find that JUNO will be able to constrain pseudo-Dirac mass splittings of $\delta m^2\gtrsim 2.9\times {10}^{-13}{\mathrm{eV}}^2$ for the scenario including $pp$ solar neutrinos, and $\delta m^2\gtrsim 1.9\times {10}^{-12}{\mathrm{eV}}^2$ when the measurement only considers ${}^7\mathrm{Be}$ monochromatic neutrinos, at the $3\sigma$ C.L. Thus, including $pp$ neutrinos will be crucial for JUNO to improve current constraints on the pseudo-Dirac scenario from solar neutrinos.

We clarify the meaning of spatial densities of hadrons. A physical density is given by the expectation value of a local operator for a physical state, and depends on both the internal structure and the hadron’s wave packet. In some particular cases, the physical density can be written as a convolution between a density function that depends on the internal structure but not the wave packet, and a smearing function that depends on the wave packet but not the internal structure. We show that the light front densities often encountered in the literature have this property but that instant form densities do not. For hadrons prepared in broad wave packets, physical instant form densities approximately obey such a convolution relation, with Breit frame densities as the apparent internal densities. However, there is an infinite series of relativistic corrections to this convolution formula.

A search for $CP$ and $P$ violation in charmless four-body $B^0\to p\overline{p}{K}^{+}{\pi }^{-}$ decays is performed using triple-product asymmetry observables. It is based on proton-proton collision data collected by the LHCb experiment at center-of-mass energies of 7, 8 and 13 TeV, corresponding to a total integrated luminosity of $8.4{\mathrm{fb}}^{-1}$. The $CP$- and $P$-violating asymmetries are measured both in the integrated phase space and in specific regions. No evidence is seen for $CP$ violation. $P$-parity violation is observed at a significance of 5.8 standard deviations.

We present a measurement of the $\tau$-lepton mass using a sample of about 175 million $e^{+}{e}^{-}\to {\tau }^{+}{\tau }^{-}$ events collected with the Belle II detector at the SuperKEKB $e^{+}{e}^{-}$ collider at a center-of-mass energy of 10.579 GeV. This sample corresponds to an integrated luminosity of $190{\mathrm{fb}}^{-1}$. We use the kinematic edge of the $\tau$ pseudomass distribution in the decay ${\tau }^{-}\to {\pi }^{-}{\pi }^{+}{\pi }^{-}{\nu }_{\tau }$ and measure the $\tau$ mass to be $1777.09\pm 0.08\pm 0.11\mathrm{MeV}/c^2$, where the first uncertainty is statistical and the second systematic. This result is the most precise to date.

Higgs boson production via gluon-gluon fusion and vector-boson fusion in proton-proton collisions is measured in the $H\to W{W}^{*}\to e\nu \mu \nu$ decay channel. The Large Hadron Collider delivered proton-proton collisions at a center-of-mass energy of 13 TeV between 2015 and 2018, which were recorded by the ATLAS detector, corresponding to an integrated luminosity of $139{\mathrm{fb}}^{-1}$. The total cross sections for Higgs boson production by gluon-gluon fusion and vector-boson fusion times the $H\to W{W}^{*}$ branching ratio are measured to be $12.0\pm 1.4$ and $0.75{}_{-0.16}^{+0.19}\mathrm{pb}$, respectively, in agreement with the Standard Model predictions of $10.4\pm 0.6$ and $0.81\pm 0.02\mathrm{pb}$. Higgs boson production is further characterized through measurements of Simplified Template Cross Sections in a total of 11 kinematic fiducial regions.

The correct implementation of the loop quantum gravity to the early homogeneous Universe has been the subject of a long debate in the literature because the $SU(2)$ symmetry cannot be properly retained. The role of this symmetry is expressed by the Gauss constraint. Here, a nonvanishing Gauss constraint is found. However, we show that using suitable variables, it can be recast into three Abelian constraints, justifying the absence of such a symmetry in loop quantum cosmology.

The Becchi-Rouet-Stora-Tyutin (BRST) invariance of the open pure spinor superstring is examined in the presence of background superfields on a $\mathrm{D}p$-brane. We note that the background superfields introduced in this paper depend on boundary fermions. The BRST invariance leads to supersymmetric Dirac-Born-Infeld (DBI) equations for background superfields depending on boundary fermions as well as boundary conditions on spacetime coordinates. After quantizing boundary fermions, background superfields are promoted to non-Abelian ones. As a result, we obtain the supersymmetric non-Abelian DBI equations from the supersymmetric DBI equations depending on boundary fermions. It is shown that these non-Abelian DBI equations reduce to the super-Yang-Mills equations in the limit ${\alpha }^{\prime }\to 0$. We also show the nilpotency of the BRST transformation of boundary fermions.