We investigate the effects of strong magnetic fields on the QCD phase structure at vanishing density by solving the gluon and quark gap equations, and by studying the dynamics of the quark scattering with the four-Fermi coupling. The chiral crossover temperature as well as the chiral condensate are computed. For asymptotically large magnetic fields we find magnetic catalysis, while we find inverse magnetic catalysis for intermediate magnetic fields. Moreover, for large magnetic fields the chiral phase transition for massless quarks turns into a crossover. The underlying mechanisms are then investigated analytically within a few simplifications of the full numerical analysis. We find that a combination of gluon screening effects and the weakening of the strong coupling is responsible for the phenomenon of inverse catalysis. In turn, the magnetic catalysis for large magnetic fields is already indicated by simple arguments based on dimensionality.

The magnetic moments of heavy sextet $J^P={\frac{1}{2}}^{+}$ baryons are calculated in the framework of the light cone QCD sum rules method. Linearly independent relations among the magnetic moments of these baryons are obtained. The results for the magnetic moments of heavy baryons obtained in this work are compared with the predictions of the other approaches.

We extend the picture of $B$-meson decay constants obtained in lattice QCD beyond those of the $B$, $B_s$ and $B_c$ to give the first full lattice QCD results for the $B^{*}$, $B_s^{*}$ and $B_c^{*}$. We use improved nonrelativistic QCD for the valence $b$ quark and the highly improved staggered quark (HISQ) action for the lighter quarks on gluon field configurations that include the effect of $u/d$, $s$ and $c$ quarks in the sea with $u/d$ quark masses going down to physical values. For the ratio of vector to pseudoscalar decay constants, we find $f_{B^{*}}/f_B=0.941(26)$, $f_{B_s^{*}}/f_{B_s}=0.953(23)$ (both $2\sigma$ less than 1.0) and $f_{B_c^{*}}/f_{B_c}=0.988(27)$. Taking correlated uncertainties into account we see clear indications that the ratio increases as the mass of the lighter quark increases. We compare our results to those using the HISQ formalism for all quarks and find good agreement both on decay constant values when the heaviest quark is a $b$ and on the dependence on the mass of the heaviest quark in the region of the $b$. Finally, we give an overview plot of decay constants for gold-plated mesons, the most complete picture of these hadronic parameters to date.

Recent experimental results for the ratios of the branching fractions of the decays $\overline{B}\to D^{(*)}\tau \overline{\nu }$ and $\overline{B}\to D^{(*)}\mu \overline{\nu }$ came as a surprise and lead to a discussion of possibility of testing new physics beyond the standard model through these modes. We show that these decay channels can provide us with good constraints on new physics and several new physics cases are favored by the present experimental data. In order to discriminate various new physics scenarios, we examine the $q^2$ distributions and estimate the sensitivity of this potential measurement at the SuperKEKB/Belle II experiment.

Transverse spectra of both jets and hadrons obtained in high-energy $pp$ and $p\overline{p}$ collisions at central rapidity exhibit power-law behavior of $1/p_T^n$ at high $p_T$. The power index $n$ is 4–5 for jet production and is 6–10 for hadron production. Furthermore, the hadron spectra spanning over 14 orders of magnitude down to the lowest $p_T$ region in $pp$ collisions at the LHC can be adequately described by a single nonextensive statistical mechanical distribution that is widely used in other branches of science. This suggests indirectly the possible dominance of the hard-scattering process over essentially the whole $p_T$ region at central rapidity in high-energy $pp$ and $p\overline{p}$ collisions. We show here direct evidences of such a dominance of the hard-scattering process by investigating the power indices of UA1 and ATLAS jet spectra over an extended $p_T$ region and the two-particle correlation data of the STAR and PHENIX collaborations in high-energy $pp$ and $p\overline{p}$ collisions at central rapidity. We then study how the showering of the hard-scattering product partons alters the power index of the hadron spectra and leads to a hadron distribution that may be cast into a single-particle nonextensive statistical mechanical distribution. Because of such a connection, the nonextensive statistical mechanical distribution may be considered as a lowest-order approximation of the hard-scattering of partons followed by the subsequent process of parton showering that turns the jets into hadrons, in high-energy $pp$ and $p\overline{p}$ collisions.

We study the implications of the LHC heavy neutral Higgs boson search data on the aligned two Higgs doublet model with a softly broken $Z_2$ symmetry. When $\tan \beta$ is small, the gluon fusion production of the heavy $CP$-even scalar $H^0$ or the $CP$-odd scalar $A^0$ becomes large enough to constrain the model by the current $\gamma \gamma$, ${\tau }^{+}{\tau }^{-}$, and $t\overline{t}$ data. By reinvestigating the indirect constraints from $\mathrm{\Delta }\rho$, $b\to s\gamma$, $\mathrm{\Delta }{M}_{B_d}$, $R_b$, ${ϵ}_K$, and the perturbativity of the running top quark Yukawa coupling, we find that the small $\tan \beta$ region is still allowed: for instance, $\tan \beta \gtrsim 0.6(0.5)$ for Type I and X (II and Y) for $m_{H^{\pm }}=800\mathrm{GeV}$. We find that the current LHC results of the heavy Higgs searches at $\sqrt{s}=8\mathrm{TeV}$ are shown to put on more significant bounds. If $m_H\simeq m_A$, the $t\overline{t}$ mode excludes $\tan \beta \lesssim 1.5$ for $m_{H,A}=500–600\mathrm{GeV}$ in all four types, and the $\gamma \gamma$ and ${\tau }^{+}{\tau }^{-}$ modes exclude $\tan \beta \lesssim 1–3$ ($\tan \beta \lesssim 3–10$) for $m_{H,A}=150–340\mathrm{GeV}$ in Types I, II, and Y (Type X).

The differential charged jet cross sections, jet fragmentation distributions, and jet shapes are measured in minimum bias proton-proton collisions at center-of-mass energy $\sqrt{s}=7\mathrm{TeV}$ using the ALICE detector at the LHC. Jets are reconstructed from charged particle momenta in the midrapidity region using the sequential recombination $k_{\mathrm{T}}$ and anti-$k_{\mathrm{T}}$ as well as the SISCone jet finding algorithms with several resolution parameters in the range $R=0.2–0.6$. Differential jet production cross sections measured with the three jet finders are in agreement in the transverse momentum ($p_{\mathrm{T}}$) interval $20<p_{\mathrm{T}}^{\text{jet},\mathrm{ch}}<100\mathrm{GeV}/c$. They are also consistent with prior measurements carried out at the LHC by the ATLAS Collaboration. The jet charged particle multiplicity rises monotonically with increasing jet $p_{\mathrm{T}}$, in qualitative agreement with prior observations at lower energies. The transverse profiles of leading jets are investigated using radial momentum density distributions as well as distributions of the average radius containing 80% ($⟨R_{80}⟩$) of the reconstructed jet $p_{\mathrm{T}}$. The fragmentation of leading jets with $R=0.4$ using scaled $p_{\mathrm{T}}$ spectra of the jet constituents is studied. The measurements are compared to model calculations from event generators (PYTHIA, PHOJET, HERWIG). The measured radial density distributions and $⟨R_{80}⟩$ distributions are well described by the PYTHIA model (tune Perugia-2011). The fragmentation distributions are better described by HERWIG.

We study two distinct $\theta$-exact Seiberg-Witten (SW) map expansions, (I) and (II), respectively, up to order $e^3$ for the gauge parameter, gauge field, and gauge field strengths of the noncommutative ${\mathrm{U}}_{\star }(1)$ gauge theory on the Moyal space. We derive explicitly the closed-form expression for the SW map ambiguity between the two and observe the emergence of several new totally commutative generalized star products. We also identify the additional gauge freedoms within each of the $e^3$-order field-strength expansions and define corresponding sets of deformation/ratio/weight parameters, $(\kappa ,{\kappa }_i)$ and $(\kappa ,{\kappa }_i^{\prime })$, for these two SW maps, respectively.

Using a cylindrical soliton solution to the four-dimensional vacuum Einstein equation, we study the nonlinear effects of gravitational waves, such as Faraday rotation and the time-shift phenomenon. In a previous work, we analyzed the single-soliton solution constructed using Pomeransky’s improved inverse scattering method. In this work, we construct a new two-soliton solution with complex-conjugate poles, by which we can avoid the light-cone singularities that are unavoidable in a single-soliton case. In particular, we compute the amplitudes of nonlinear gravitational waves and the time dependence of the polarizations. Furthermore, we consider the time-shift phenomenon for soliton waves, which means that a wave packet can propagate at a velocity slower than light.

We entertain a new paradigm according to which the observed matter-antimatter asymmetry is generated as a large-scale quantum fluctuation over the baryon-symmetric state that occurred during the cosmic inflation.

In this paper we generalize the kinetic mixing idea to time reparametrization invariant theories, namely, relativistic point particles and cosmology in order to obtain new insights for dark matter and energy. In the first example, two relativistic particles interact through an appropriately chosen coupling term. It is shown that the system can be diagonalized by means of a nonlocal field redefinition, and, as a result of this procedure, the mass of one the particles gets rescaled. In the second case, inspired by the previous example, two cosmological models (each with its own scale factor) are made to interact in a similar fashion. The equations of motion are solved numerically in different scenarios (dust, radiation or a cosmological constant coupled to each sector of the system). When a cosmological constant term is present, kinetic mixing rescales it to a lower value which may be more amenable to observations.

The separation of the faint cosmological background signal from bright astrophysical foregrounds remains one of the most daunting challenges of mapping the high-redshift intergalactic medium with the redshifted 21 cm line of neutral hydrogen. Advances in mapping and modeling of diffuse and point source foregrounds have improved subtraction accuracy, but no subtraction scheme is perfect. Precisely quantifying the errors and error correlations due to missubtracted foregrounds allows for both the rigorous analysis of the 21 cm power spectrum and for the maximal isolation of the “EoR window” from foreground contamination. We present a method to infer the covariance of foreground residuals from the data itself in contrast to previous attempts at a priori modeling. We demonstrate our method by setting limits on the power spectrum using a 3 h integration from the 128-tile Murchison Widefield Array. Observing between 167 and 198 MHz, we find at 95% confidence a best limit of ${\mathrm{\Delta }}^2(k)<3.7\times {10}^4{\mathrm{mK}}^2$ at comoving scale $k=0.18h{\mathrm{Mpc}}^{-1}$ and at $z=6.8$, consistent with existing limits.

We study direct $CP$-violating asymmetries (CPAs) in the two-body ${\mathrm{\Lambda }}_b$ decays of ${\mathrm{\Lambda }}_b\to pM(V)$ with $M(V)=K^{-}(K^{*-})$ and ${\pi }^{-}({\rho }^{-})$ based on the generalized factorization method in the standard model (SM). After simultaneously explaining the observed decay branching ratios of ${\mathrm{\Lambda }}_b\to (p{K}^{-},p{\pi }^{-})$ with ${\mathcal{R}}_{\pi K}\equiv \mathcal{B}({\mathrm{\Lambda }}_b\to p{\pi }^{-})/\mathcal{B}({\mathrm{\Lambda }}_b\to p{K}^{-})$ being $0.84\pm 0.09$, we find that their corresponding direct CPAs are $(5.8\pm 0.2,-3.9\pm 0.2)\%$, in comparison with $(-5_{-5}^{+26},-31_{-1}^{+43})\%$ based on the perturbative QCD calculation and $(-10\pm 8\pm 4,6\pm 7\pm 3)\%$ from the CDF experiment, respectively. For ${\mathrm{\Lambda }}_b\to (p{K}^{*-},p{\rho }^{-})$, the decay branching ratios and CPVs are predicted to be $(2.5\pm 0.5,11.4\pm 2.1)\times {10}^{-6}$ with ${\mathcal{R}}_{\rho K^{*}}=4.6\pm 0.5$ and $(19.6\pm 1.6,-3.7\pm 0.3)\%$, respectively. The uncertainties for the CPAs in these decay modes as well as ${\mathcal{R}}_{\pi K,\rho K^{*-}}$ mainly arise from the quark mixing elements and nonfactorizable effects, whereas those from the hadronic matrix elements are either totally eliminated or small. We point out that the large CPA for ${\mathrm{\Lambda }}_b\to p{K}^{*-}$ is promising to be measured by the CDF and LHCb experiments, which is a clean test of the SM.

A search has been performed for pair production of heavy vectorlike down-type ($B$) quarks. The analysis explores the lepton-plus-jets final state, characterized by events with one isolated charged lepton (electron or muon), significant missing transverse momentum, and multiple jets. One or more jets are required to be tagged as arising from $b$ quarks, and at least one pair of jets must be tagged as arising from the hadronic decay of an electroweak boson. The analysis uses the full data sample of $pp$ collisions recorded in 2012 by the ATLAS detector at the LHC, operating at a center-of-mass energy of 8 TeV, corresponding to an integrated luminosity of $20.3{\mathrm{fb}}^{-1}$. No significant excess of events is observed above the expected background. Limits are set on vectorlike $B$ production, as a function of the $B$ branching ratios, assuming the allowable decay modes are $B\to Wt/Zb/Hb$. In the chiral limit with a branching ratio of 100% for the decay $B\to Wt$, the observed (expected) 95% C.L. lower limit on the vectorlike $B$ mass is 810 GeV (760 GeV). In the case where the vectorlike $B$ quark has branching ratio values corresponding to those of an $SU(2)$ singlet state, the observed (expected) 95% C.L. lower limit on the vectorlike $B$ mass is 640 GeV (505 GeV). The same analysis, when used to investigate pair production of a colored, charge $5/3$ exotic fermion $T_{5/3}$, with subsequent decay $T_{5/3}\to Wt$, sets an observed (expected) 95% C.L. lower limit on the $T_{5/3}$ mass of 840 GeV (780 GeV).

This paper presents a measurement of the charged current interaction rate of the electron neutrino beam component of the beam above 1.5 GeV using the large fiducial mass of the T2K ${\pi }^0$ detector. The predominant portion of the ${\nu }_e$ flux ($\sim 85\%$) at these energies comes from kaon decays. The measured ratio of the observed beam interaction rate to the predicted rate in the detector with water targets filled is $0.89\pm 0.08(\text{stat})\pm 0.11(\text{sys})$, and with the water targets emptied is $0.90\pm 0.09(\text{stat})\pm 0.13(\text{sys})$. The ratio obtained for the interactions on water only from an event subtraction method is $0.87\pm 0.33(\text{stat})\pm 0.21(\text{sys})$. This is the first measurement of the interaction rate of electron neutrinos on water, which is particularly of interest to experiments with water Cherenkov detectors.

We study extremal surfaces in de Sitter space in the Poincare slicing in the upper patch, anchored on spatial subregions at the future boundary ${\mathcal{I}}^{+}$, restricted to constant boundary Euclidean time slices (focusing on strip subregions). We find real extremal surfaces of minimal area as the boundaries of past light-cone wedges of the subregions in question: these are null surfaces with vanishing area. We also find complex extremal surfaces as complex extrema of the area functional, and the area is not always real valued. In ${\mathrm{dS}}_4$ the area is real. The area has structural resemblance with entanglement entropy in a dual conformal field theory. There are parallels with analytic continuation from the Ryu-Takayanagi expressions for holographic entanglement entropy in anti-de Sitter. We also discuss extremal surfaces in the de Sitter (dS) black brane and the de Sitter “bluewall” studied previously. The ${\mathrm{dS}}_4$ black brane complex surfaces exhibit a real finite cutoff-independent extensive piece. In the bluewall geometry, there are real surfaces that go from one asymptotic universe to the other through the Cauchy horizons.

Recent investigations have revealed powerful selection rules for resonant energy transfer between modes of nonlinear perturbations in global anti–de Sitter (AdS) space-time. It is likely that these selection rules are due to the highly symmetric nature of the underlying AdS background, though the precise relation has remained unclear. In this article, we demonstrate that the equation satisfied by the scalar field mode functions in ${\mathrm{AdS}}_{d+1}$ has a hidden $SU(d)$ symmetry, and explicitly specify the multiplets of this $SU(d)$ symmetry furnished by the mode functions. We also comment on the role this structure might play in explaining the selection rules.

We study nonperturbative multiphoton electron-positron pair creation in ultrastrong electromagnetic fields formed by two counterpropagating pulses with elliptic polarization. Our numerical approach allows us to take into account the temporal as well as the spatial variation of the standing electromagnetic field. The spin and momentum resolved pair creation probabilities feature characteristic Rabi oscillations and resonance spectra. Therefore, each laser frequency features a specific momentum distribution of the created particles. We find that, depending on the relative polarization of both pulses, the created electrons may be spin polarized along the direction of field propagation.

We study $\mathcal{N}=1$ supersymmetric gauge theories coupled with higher derivative chiral models in four dimensions in the off-shell superfield formalism. We solve the equation of motion for the auxiliary fields and find two distinct on-shell structures of the Lagrangian that we call the canonical and noncanonical branches characterized by zero and nonzero auxiliary fields, respectively. We classify Bogomol’nyi-Prasado-Sommerfield (BPS) states of the models in Minkowski and Euclidean spaces. In Minkowski space, we find Abelian and non-Abelian vortices, vortex lumps (or gauged lumps with fractional lump charges) as $1/2$ BPS states in the canonical branch, and higher derivative generalization of vortices and vortex-(BPS)baby Skyrmions (or gauged BPS baby Skyrmions with fractional baby Skyrme charges) as $1/4$ BPS states in the noncanonical branch. In four-dimensional Euclidean space, we find Yang-Mills instantons trapped inside a non-Abelian vortex, intersecting vortices, and intersecting vortex-(BPS)baby Skyrmions as $1/4$ BPS states in the canonical branch but no BPS states in the noncanonical branch other than those in the Minkowski space.

We study the geodesics of a five-dimensional nonasymptotically flat dilatonic 2-brane. Although the metric’s warp function diverges logarithmically in the far field region of the transverse space, the curvature does not. The brane has two naked singularities, the usual central singularity and a circular singularity at the radius where the warp function vanishes. This creates two causally disconnected regions of the transverse space. Using the methods of energy conservation and effective potentials, we study the null and timelike orbital and radial geodesics in both regions and show that they exhibit opposing energy requirements.