By lowering their energy threshold, direct dark matter searches can reach the neutrino floor with experimental technology that is now in development. The ${}^7\mathrm{Be}$ flux can be detected with $\sim 10\mathrm{eV}$ nuclear recoil energy threshold and 50 kg/yr exposure. The $pep$ flux can be detected with $\sim 3$ ton/yr exposure, and the first detection of the CNO flux is possible with similar exposure. The $pp$ flux can be detected with threshold of $\sim \mathrm{eV}$ and only $\sim \mathrm{kg}/\mathrm{yr}$ exposure. These can be the first pure neutral current measurements of the low-energy solar neutrino flux. Measuring this flux is important for low mass dark matter searches and for understanding the solar interior.

In recent work we proposed a novel theory of dark matter (DM) superfluidity that matches the successes of the $\mathrm{\Lambda }\mathrm{CDM}$ model on cosmological scales while simultaneously reproducing modified Newtonian dynamics (MOND) phenomenology on galactic scales. The agents responsible for mediating the MONDian force law are superfluid phonons that couple to ordinary (baryonic) matter. In this paper we propose an alternative way for the MOND phenomenon to emerge from DM superfluidity. The central idea is to use higher-gradient corrections in the superfluid effective theory. These next-to-leading order terms involve gradients of the gravitational potential, and therefore effectively modify the gravitational force law. In the process we discover a novel mechanism for generating the nonrelativistic MOND action, starting from a theory that is fully analytic in all field variables. The idea, inspired by the symmetron mechanism, uses the spontaneous breaking of a discrete symmetry. For large acceleration, the symmetry is unbroken and the action reduces to Einstein gravity. For small acceleration, the symmetry is spontaneously broken and the action reduces to MONDian gravity. Cosmologically, however, the Universe is always in the Einstein-gravity, symmetry-restoring phase. The expansion history and linear growth of density perturbations are therefore indistinguishable from $\mathrm{\Lambda }\mathrm{CDM}$ cosmology.

We show that the Planck 2015 and BICEP2/KECK measurements of the cosmic microwave background (CMB) anisotropies provide together an information gain of $0.82\pm 0.13$ bits on the reheating history over all slow-roll single-field models of inflation. This corresponds to a 40% improvement compared to the Planck 2013 constraints on the reheating. Our method relies on an exhaustive CMB data analysis performed over nearly 200 models of inflation to derive the Kullback-Leibler entropy between the prior and the fully marginalized posterior of the reheating parameter. This number is a weighted average by the Bayesian evidence of each model to explain the data thereby ensuring its fairness and robustness.

We calculate the electric conductivity of a gas of relativistic particles with isotropic cross sections using the Boltzmann equation as the starting point. Our analysis is restricted to elastic collisions. We show the perfect agreement with previously published numerical results for a massless quark-gluon plasma, and give results for the electric conductivity of an interacting hadron gas, employing realistic resonance cross sections. These results for the electric conductivity of a hot hadron gas, as created in (ultra)relativistic heavy-ion collisions, are of rich phenomenological as well as theoretical interest and can be compared to, e.g., lattice quantum field theory calculations.

Using the QCD sum rule approach, we investigate the possible four-quark structure for the new observed $B_s^0{\pi }^{\pm }$ narrow structure (D0). We use a diquak-antidiquark scalar current and work to the order of $m_s$ in full QCD, without relying on $1/m_Q$ expansion. Our study indicates that although it is possible to obtain a stable mass in agreement with the state found by the D0 collaboration, more constraint analysis (simultaneous requirement of the OPE convergence and the dominance of the pole on the phenomenological side) leads to a higher mass. We also predict the masses of the bottom scalar tetraquark resonances with zero and two strange quarks.

We study all implementations of the $S_3$ symmetry in the two Higgs doublet models with quarks, consistent with nonzero quark masses and a Cabibbo-Kobayashi-Maskawa (CKM) matrix, which is not block diagonal. We study the impact of the various soft-breaking terms and vacuum expectation values and find an interesting relation between the mixing angles $\alpha$ and $\beta$. We also show that, in this minimal setting, only two types of assignments are possible: Either all field sectors are in singlets or all field sectors have a doublet.

The observability of a gluino at LHC run II is analyzed for the case where the gluino lies in the gluino-neutralino coannihilation region and the mass gap between the gluino and the neutralino is small. The analysis is carried out under the Higgs boson mass constraint and the constraint of dark matter relic density consistent with WMAP and Planck experiments. It is shown that in this case a gluino with mass much smaller than the current lower limit of $\sim 1500\mathrm{GeV}$ as given by LHC run II at $3.2{\mathrm{fb}}^{-1}$ of integrated luminosity would have escaped detection. The analysis is done using the signal regions used by the ATLAS Collaboration where an optimization of signal regions was carried out to determine the best regions for gluino discovery in the gluino-neutralino coannihilation region. It is shown that under the Higgs boson mass constraint and the relic density constraint, a gluino mass of $\sim 700\mathrm{GeV}$ would require $14{\mathrm{fb}}^{-1}$ of integrated luminosity for discovery and a gluino of mass $\sim 1250\mathrm{GeV}$ would require $3400{\mathrm{fb}}^{-1}$ of integrated luminosity for discovery at LHC run II. An analysis of dark matter for this case is also given. It is found that for the range of gluino masses considered, the neutralino mass lies within less than 100 GeV of the gluino mass. Thus a measurement of the gluino mass in the gluino-neutralino coannihilation region will provide a determination of the neutralino mass. In this region the neutralino is dominantly a gaugino and the spin-independent proton-neutralino cross section is small but much larger than the neutrino floor lying in the range $\sim (1–10)\times {10}^{-47}{\mathrm{cm}}^2$. Thus a significant part of the parameter space of the model will lie within the reach of the next generation LUX-ZEPLIN dark matter experiment.

In this work, we investigate the possibility of probing a class of neutrino mass models at the LHC proton-proton collisions with 8 and 14 TeV energies. The existence of lepton flavor violating interactions for a singlet charged scalar, $S^{\pm }$, that couples to the leptons could induce many processes such as $pp\to {\ell }_{\alpha }^{\pm }{\ell }_{\beta }^{\mp }+\cancel{E}$. Using the processes with ${\ell }_{\alpha }{\ell }_{\beta }=ee$, $e\mu$, $\mu \mu$, we found that an inclusive cut on the $M_{T2}$ event variable is vital in our analysis and leads to an effective suppression of the large Standard Model background. Our results show possible detectability of the charged scalars effect, especially at the $\sqrt{s}=14\mathrm{TeV}$.

We study the quark flavor violating Higgs boson decay $h\to \overline{b}s+b\overline{s}$ in the minimal supersymmetric standard model (MSSM). The decay is analyzed first in a model-independent approach and second in the minimal flavor violating (MFV) constrained MSSM. The experimental constraints from $B$-physics observables (BPO) and electroweak precision observables (EWPO) are also calculated and imposed on the parameter space. It is shown that, in some cases, the EWPO restrict the flavor violating parameter space more than the BPO. In the model-independent analysis, values of $\mathcal{O}(10^{-4})$ can be found for $\mathrm{BR}(h\to \overline{b}s+b\overline{s})$. In the MFV constrained MSSM (CMSSM), such results can only be obtained in very restricted parts of the parameter space. The results show that observation of the decay $h\to \overline{b}s+b\overline{s}$ in the MSSM at future $e^{+}{e}^{-}$ colliders is not excluded.

A solution to the sign problem is the so-called “Lefschetz thimble approach” where the domain of integration for field variables in the path integral is deformed from the real axis to a submanifold in the complex space. For properly chosen submanifolds (“thimbles”) the sign problem disappears or is drastically alleviated. The parametrization of the thimble by real coordinates requires the calculation of a Jacobian with a computational cost of order $\mathcal{O}(V^3)$, where $V$ is proportional to the spacetime volume. In this paper we propose two estimators for this Jacobian with a computational cost of order $\mathcal{O}(V)$. We discuss analytically the regimes where we expect the estimator to work and show numerical examples in two different models.

We investigate the properties of asymmetric quark matter and strange quark matter in the framework of the SU(3) Nambu–Jona-Lasinio (NJL) model with two types of vector interactions: (1) the flavor-dependent repulsion among different flavors of quarks with the coupling constant $G_V$, and (2) the universal repulsion and the vector-isovector interaction among different flavors of quarks with the coupling constants $g_V$ and $G_{IV}$. Using these two types of vector interactions in the NJL model, we study the quark symmetry energy in asymmetric quark matter, the constituent quark mass, the quark fraction, the equation of state in strange quark matter, the maximum mass of a quark star, and the properties of the QCD phase diagram. We find that including the two types of vector interactions in the SU(3) NJL model can significantly influence the quark matter symmetry energy as well as the properties of strange quark matter and quark stars. In particular, our results indicate that we can describe PSR $\mathrm{J}1614-2230$ and PSR $\mathrm{J}0348+0432$ as quark stars by considering the universal repulsion and the vector-isovector interaction among quark matter in the SU(3) NJL model.

In a series of papers, Bardeen, Buras and Gérard have proposed a large-$N_c$ method to evaluate hadronic weak matrix elements to attack, for instance, the determination of the $\mathrm{\Delta }I=1/2$ rule and $\mathrm{Re}({\epsilon }^{\prime }/\epsilon )$. Here we test this method to the determination of the form factor parameters $a_{+}$ and $b_{+}$ in the decays $K^{+}\to {\pi }^{+}{\ell }^{+}{\ell }^{-}$ and $K_S\to {\pi }^0{\ell }^{+}{\ell }^{-}$. The results are encouraging, in particular after a complete treatment of vector meson dominance.

We investigate long-range rapidity correlations of pairs of prompt photons and jets in the color glass condensate framework in proton-proton and proton-nucleus collisions at RHIC and the LHC. We show that photon-jet correlations exhibit long-range azimuthal collimation at the near side for low transverse momenta of the produced photon and jet in high-multiplicity events. These ridge-like features are strikingly similar to the observed ridge effect for dihadron correlations at RHIC and the LHC. We show that correlations in the relative rapidity and the relative azimuthal angle between pairs of prompt photons and jets strongly depend on the gluon saturation dynamics at small-$x$ kinematics and such measurements can help to understand the true origin of the observed dihadron ridge in $p+A$ collisions, and address whether the ridge is a universal phenomenon for all two-particle correlations at high-energy and high-multiplicity events. We also investigate whether there is a ridge-like structure for photon-hadron pair correlations at RHIC and the LHC. We find that the hadronization of jets has nontrivial effects on the photon-jet correlations.

In an experiment currently being performed at the Institute for High Energy Physics, Serpukhov, Russia, a beam of charged kaons is directed on a copper target. In the electromagnetic field of the target nuclei, two reactions occur: $K^{+}\gamma \to K^{+}{\pi }^0$ and $K^{+}\gamma \to K^0{\pi }^{+}$. A peculiar distinction between these two reactions is that there is a chiral anomaly contribution in the former reaction, but not in the latter. This contribution can be directly seen through comparison of the cross sections of these reactions near the threshold. We derive expressions for these cross sections taking into account the anomaly and the contribution of the lightest vector mesons.

We study the effects of nonstandard interactions on the oscillation pattern of atmospheric neutrinos. We use neutrino oscillograms as our main tool to infer the role of nonstandard interactions (NSI) parameters at the probability level in the energy range, $E\in [1,20]\mathrm{GeV}$ and zenith angle range, $\cos \theta \in [-1,0]$. We compute the event rates for atmospheric neutrino events in presence of NSI parameters in the energy range $E\in [1,10]\mathrm{GeV}$ for two different detector configurations—a magnetized iron calorimeter and an unmagnetized liquid argon time projection chamber which have different sensitivities to NSI parameters due to their complementary characteristics.

A search for supersymmetry in hadronic final states with highly boosted $W$ bosons and $b$ jets is presented, focusing on compressed scenarios. The search is performed using proton-proton collision data at a center-of-mass energy of 8 TeV, collected by the CMS experiment at the LHC, corresponding to an integrated luminosity of $19.7{\mathrm{fb}}^{-1}$. Events containing candidates for hadronic decays of boosted $W$ bosons are identified using jet substructure techniques, and are analyzed using the razor variables $M_R$ and $R^2$, which characterize a possible signal as a peak on a smoothly falling background. The observed event yields in the signal regions are found to be consistent with the expected contributions from standard model processes, which are predicted using control samples in the data. The results are interpreted in terms of gluino-pair production followed by their exclusive decay into top squarks and top quarks. The analysis excludes gluino masses up to 1.1 TeV for light top squarks decaying solely to a charm quark and a neutralino, and up to 700 GeV for heavier top squarks decaying solely to a top quark and a neutralino.

We present electric-magnetic (EM)-duality formulations for non-Abelian gauge groups with $N=1$ supersymmetry in $D=3+3$ and $5+5$ space-time dimensions. We show that these systems generate self-dual $N=1$ supersymmetric Yang-Mills (SDSYM) theory in $D=2+2$. For a $N=2$ supersymmetric EM-dual system in $D=3+3$, we have the Yang-Mills multiplet $({A_{\mu }}^I,{{\lambda }_A}^I)$ and a Hodge-dual multiplet $({B_{\mu \nu \rho }}^I,{{\chi }_A}^I)$, with an auxiliary tensors ${C_{\mu \nu \rho \sigma }}^I$ and $K_{\mu \nu }$. Here, $I$ is the adjoint index, while $A$ is for the doublet of $Sp(1)$. The EM-duality conditions are ${F_{\mu \nu }}^I=(1/4!){{\epsilon }_{\mu \nu }}^{\rho \sigma \tau \lambda }{G_{\rho \sigma \tau \lambda }}^I$ with its superpartner duality condition ${{\lambda }_A}^I=-{{\chi }_A}^I$. Upon appropriate dimensional reduction, this system generates SDSYM in $D=2+2$. This system is further generalized to $D=5+5$ with the EM-duality condition ${F_{\mu \nu }}^I=(1/8!){{\epsilon }_{\mu \nu }}^{{\rho }_1\cdots {\rho }_8}{G_{{\rho }_1\cdots {\rho }_8}}^I$ with its superpartner condition ${\lambda }^I=-{\chi }^I$. Upon appropriate dimensional reduction, this theory also generates SDSYM in $D=2+2$. As long as we maintain Lorentz covariance, $D=5+5$ dimensions seems to be the maximal space-time dimensions that generate SDSYM in $D=2+2$. Namely, EM-dual system in $D=5+5$ serves as the Master Theory of all supersymmetric integrable models in dimensions $1\le D\le 3$.

The present article can be considered as a complement to the work of Phys. Rev. D 93, 045002 (2016), where an nonperturbative approach to QED with $x$-electric critical potential steps was developed. In the beginning, we study conditions when in and out spaces of the QED under consideration are unitarily equivalent. Then, we construct a general density operator with the vacuum initial condition. Such an operator describes a deformation of the initial vacuum state by $x$-electric critical potential steps. We construct reductions of the deformed state to electron and positron subsystems, calculating the loss of the information in these reductions. We illustrate the general consideration studying the deformation of the quantum vacuum between two capacitor plates. Finally, we calculate the entanglement measures of these reduced matrices as von Neumann entropies.

The 4-parameter exact solution presumably describing the exterior gravitational field of a generic neutron star is presented in a concise explicit form defined by only three potentials. In the equatorial plane, the metric functions of the solution are found to be given by particularly simple expressions that make them very suitable for the use in concrete applications. Following Pappas and Apostolatos, we perform a comparison of the multipole structure of the solution with the multipole moments of the known physically realistic Berti-Stergioulas numerical models of neutron stars to argue that the hyperextreme sectors of the solution are not less (but are possibly even more) important for the correct description of rapidly rotating neutron stars than the subextreme sector involving exclusively the black-hole constituents. We have also worked out in explicit form an exact analog of the well-known Hartle-Thorne approximate metric.