The possibility of estimating the mass composition of primary cosmic rays above the knee of their energy spectrum through the study of high-energy gamma rays, muons, and neutrinos produced in the interactions of cosmic rays with solar ambient matter and radiation is explored. It is found that the theoretical fluxes of TeV gamma rays, muons, and neutrinos from a region around 15° of the Sun are sensitive to a mass composition of cosmic rays in the PeV energy range. The experimental prospects for the detection of such TeV gamma rays/neutrinos by future experiments are discussed.

A model with $L_{\mu }-L_{\tau }$ gauge symmetry is the least constrained model as a resolution to the disagreement of the muon anomalous magnetic moment between the theoretical predictions and the experimental results. In this paper, we discuss how well the $L_{\mu }-L_{\tau }$ model can be constrained by looking for decays of the charged kaon associated with a $L_{\mu }-L_{\tau }$ gauge boson. More concretely, we consider searches for single muon tracks from the decays of stopped charged kaon as in the E949 experiment. In our conservative estimation, we find that the favored parameter region for the muon anomalous magnetic moment can be tested by using a 10 times larger number of the stopped charged kaons and about a 100 times better photon rejection rate than the E949 experiment.

In the framework of the effective field theory approach to heavy supersymmetry radiative corrections in the Higgs sector of the minimal supersymmetric standard model (MSSM) for the effective potential decomposition up to the dimension-six operators are calculated. Symbolic expressions for the threshold corrections induced by $F$- and $D$-soft supersymmetry breaking terms are derived, and the Higgs boson mass spectrum respecting the condition $m_h=125\mathrm{GeV}$ for the lightest $CP$-even scalar is evaluated.

In this work, we use McGuire’s model to describe scattering of three spinless identical particles in one spatial dimension; we first present analytic solutions of Faddeev’s equation for scattering of three spinless particles in free space. The three particles interaction in finite volume is derived subsequently, and the quantization conditions by matching wave functions in free space and finite volume are presented in terms of two-body scattering phase shifts. The quantization conditions obtained in this work for the short-range interaction are Lüscher’s formula-like and consistent with Yang’s results [Phys. Rev. Lett. 19, 1312 (1967)].

The $B^{\pm }$ meson production asymmetry in $pp$ collisions is measured using $B^{+}\to {\overline{D}}^0{\pi }^{+}$ decays. The data were recorded by the LHCb experiment during Run 1 of the LHC at center-of-mass energies of $\sqrt{s}=7$ and 8 TeV. The production asymmetries, integrated over transverse momenta in the range $2<p_{\mathrm{T}}<30\mathrm{GeV}/c$, and rapidities in the range $2.1<y<4.5$ are measured to be ${\mathcal{A}}_{\mathrm{prod}}(B^{+},\sqrt{s}=7\mathrm{TeV})=(-0.41\pm 0.49\pm 0.10)\times {10}^{-2}$, ${\mathcal{A}}_{\mathrm{prod}}(B^{+},\sqrt{s}=8\mathrm{TeV})=(-0.53\pm 0.31\pm 0.10)\times {10}^{-2}$, where the first uncertainties are statistical and the second are systematic. These production asymmetries are used to correct the raw asymmetries of $B^{+}\to J/\psi K^{+}$ decays, thus allowing a measurement of the $CP$ asymmetry, ${\mathcal{A}}_{CP}(B^{+}\to J/\psi K^{+})=(0.09\pm 0.27\pm 0.07)\times {10}^{-2}$.

We study the behavior of entanglement between different degrees of freedom of scattering fermions, based on an exemplary QED scattering process $e^{+}{e}^{-}\to {\mu }^{+}{\mu }^{-}$. The variation of entanglement entropy between two fermions from an initial state to the final state was computed, with respect to different entanglement between the ingoing particles. This variation of entanglement entropy is found to be proportional to an area quantity, the total cross section. We also study the spin-momentum and helicity-momentum entanglements within one particle in the aforementioned scattering process. The calculations of the relevant variations of mutual information in the same inertial frame reveals that, for a maximally entangled initial state, the scattering between the particles does not affect the degree of both of these entanglements of one particle in the final state. It is also found that the increasing degree of entanglement between two ingoing particles would restrict the generation of entanglement between spin (helicity) and momentum of one outgoing particle. And the entanglement between spin and momentum within one particle in the final state is shown to always be stronger than that for helicity-momentum for a general initial entanglement state, implying significantly distinct properties of entanglement for the helicity and spin perceived by an inertial observer.

We explicitly solved the anomaly-free quantum constraints proposed by Tomlin and Varadarajan for the weak Euclidean model of canonical loop quantum gravity, in a large subspace of the model’s kinematic Hilbert space, which is the space of the charge network states. In doing so, we first identified the subspace on which each of the constraints acts convergingly, and then by explicitly evaluating such actions we found the complete set of the solutions in the identified subspace. We showed that the space of solutions consists of two classes of states, with the first class having a property that involves the condition known from the Minkowski theorem on polyhedra, and the second class satisfying a weaker form of the spatial diffeomorphism invariance.

A class of generalized Galileon cosmological models, which can be described by a pointlike Lagrangian, is considered in order to utilize Noether’s theorem to determine conservation laws for the field equations. In the Friedmann-Lemaître-Robertson-Walker universe, the existence of a nontrivial conservation law indicates the integrability of the field equations. Because of the complexity of the latter, we apply the differential invariants approach in order to construct special power-law solutions and study their stability.

We find new solutions to the five-dimensional Einstein-Maxwell-dilaton theory with cosmological constant where the dilaton field couples to the electromagnetic field as well as to the cosmological term with two different coupling constants. The five-dimensional spacetime is nonstationary and is a conformally regular spacetime, everywhere. Both the dilaton field and the electromagnetic field depend on time and two spatial directions. The cosmological constant takes a positive, negative, or zero value, depending on the value of the coupling constant. We study the physical properties of the spacetime, and we show that the solutions are unique in five dimensions and that they cannot be uplifted to higher-dimensional Einstein-Maxwell theory or Einstein gravity in the presence of the cosmological constant. Moreover, we construct new solutions to the theory in which both coupling constants are equal.

Neutrinos mix and have mass differences, so decays from one to another must occur. But how fast? The best direct limits on nonradiative decays, based on solar and atmospheric neutrinos, are weak, $\tau \gtrsim {10}^{-3}\mathrm{s}$ ($m/\mathrm{eV}$) or much worse. Greatly improved sensitivity, $\tau \sim 10^3\mathrm{s}$ ($m/\mathrm{eV}$), will eventually be obtained using neutrinos from distant astrophysical sources, but large uncertainties—in neutrino properties, source properties, and detection aspects—do not allow this yet. However, there is a way forward now. We show that IceCube diffuse neutrino measurements, supplemented by improvements expected in the near term, can increase sensitivity to $\tau \sim 10\mathrm{s}$ ($m/\mathrm{eV}$) for all neutrino mass eigenstates. We provide a road map for the necessary analyses and show how to manage the many uncertainties. If limits are set, this would definitively rule out the long-considered possibility that neutrino decay affects solar, atmospheric, or terrestrial neutrino experiments.

Indirect detection of dark matter is a major avenue for discovery. However, baryonic backgrounds are diverse enough to mimic many possible signatures of dark matter. In this work, we study the newly proposed technique of dark matter velocity spectroscopy [E. G. Speckhard, K. C. Y. Ng, J. F. Beacom, and R. Laha, Phys. Rev. Lett. 116, 031301 (2016)]. The nonrotating dark matter halo and the Solar motion produce a distinct longitudinal dependence of the signal which is opposite in direction to that produced by baryons. Using collisionless dark matter only simulations of Milky Way like halos, we show that this new signature is robust and holds great promise. We develop mock observations by a high energy resolution x-ray spectrometer on a sounding rocket, the Micro-X experiment, to our test case, the 3.5 keV line. We show that by using six different pointings, Micro-X can exclude a constant line energy over various longitudes at $\ge 3\sigma$. The halo triaxiality is an important effect, and it will typically reduce the significance of this signal. We emphasize that this new smoking gun in motion signature of dark matter is general and is applicable to any dark matter candidate which produces a sharp photon feature in annihilation or decay.

We consider polarizable sheets, which recently received some attention, especially in the context of the dispersion interaction of thin sheets like graphene. These sheets are modeled by a collection of delta function potentials and resemble zero-range potentials, which are known in quantum mechanics. We develop a theoretical description and apply the so-called TGTG formula to calculate the interaction of two such lattices. Thereby, we make use of the formulation of the scattering of waves off such sheets provided earlier. We consider all limiting cases, providing a link to earlier results. Also, we discuss the relation to the pairwise summation method.

We show that the photon-photon fusion process contributes significantly to the pair production of doubly charged Higgs bosons at the LHC at a level comparable to the Drell-Yan production. We reinterpret the ATLAS lower limit of 570 GeV (420 GeV) on the mass of ${\mathrm{\Delta }}_L^{\pm \pm }$ (${\mathrm{\Delta }}_R^{\pm \pm }$) arising from an $SU(2{)}_L$ triplet (singlet) scalar by including the photon-initiated process, and we derive a new lower limit of 748 GeV (570 GeV), assuming that ${\mathrm{\Delta }}^{\pm \pm }$ decays into $e^{\pm }{e}^{\pm }$ 100% of the time. We have also shown that the $5\sigma$ discovery reach for ${\mathrm{\Delta }}_L^{\pm \pm }$ (${\mathrm{\Delta }}_R^{\pm \pm }$) is 846 GeV (783 GeV) with $100{\mathrm{fb}}^{-1}$ luminosity at the 13 TeV LHC. We derive a somewhat more stringent limit on the mass when the doubly charged scalar arises from higher-dimensional representations of $SU(2{)}_L$.

We study mono-Higgs signatures emerging in the $B-L$ supersymmetric standard model induced by new channels not present in the minimal supersymmetric standard model, i.e., via topologies in which the mediator is either a heavy $Z^{\prime }$, with mass of $\mathcal{O}(2\mathrm{TeV})$, or an intermediate $h^{\prime }$ (the lightest $CP$-even Higgs state of $B-L$ origin), with a mass of $\mathcal{O}(0.2\mathrm{TeV})$. The mono-Higgs probe considered is the standard model-like Higgs state recently discovered at the Large Hadron Collider, so as to enforce its mass reconstruction for background reduction purposes. With this in mind, its two cleanest signatures are selected: $\gamma \gamma$ and $Z{Z}^{*}\to 4l$ ($l=e$, $\mu$). We show how both of these can be accessed with foreseen energy and luminosity options using a dedicated kinematic analysis performed in the presence of partonic, showering, hadronization and detector effects.

The mass spectrum of $c\overline{b}$ states has been obtained using the phenomenological relativistic quark model (RQM) with coupled channel effects. The Hamiltonian used in the investigation has confinement potential and confined one gluon exchange potential (COGEP). In the frame work of the RQM, a study of magnetic dipole and electric dipole transitions and radiative decays of $c\overline{b}$ states has been made. The weak decay widths in the spectator quark approximation have been estimated. An overall agreement is obtained with the experimental masses and decay widths.

We analyze direct dark matter detection experiments for $\lesssim 100\mathrm{MeV}$ mass mediators with general interactions. We compare the nuclear recoil energy spectra from these interactions to the solar neutrino spectrum. A set of interactions that generate spectra similar to the neutrino background is identified; however, this set is distinct from those that mimic the neutrino background for $\gtrsim 100\mathrm{MeV}$ mass mediators. We outline a classification scheme based on momentum dependence of the dark matter–nucleus interaction to determine how strong the discovery limit for each interaction saturates due to the neutrino background. Our results motivate experimental progress towards lower nuclear recoil energy thresholds.

There is a dilemma in constructing interacting scale invariant Euclidean field theories that are not conformal invariant. On one hand, scale invariance without conformal invariance seems more generic by requiring only a smaller symmetry. On the other hand, the existence of a nonconserved current with exact scaling dimension $d-1$ in $d$ dimensions seems to require extra fine-tuning. To understand the competition better, we explore some examples without the reflection positivity. We show that a theory of elasticity (also known as Riva-Cardy theory) coupled with massless fermions in $d=4-\epsilon$ dimensions does not possess an interacting scale invariant fixed point except for an unstable (and unphysical) one with an infinite coefficient of compression. We do, however, find interacting scale invariant but nonconformal field theories in gauge fixed versions of the Banks-Zaks fixed points in $d=4$ dimensions.

We consider radiative processes of an atom in a rotating black-hole background. We assume the atom, represented by a hypothetical two-level system, is coupled via a monopole interaction with a massless quantum scalar field prepared in each one of the usual physical vacuum states of interest. We constrain ourselves to two different states of motion for the atom, namely a static situation in which the atom is placed at a fixed radial distance, and also the case in which it has a stationary motion but with zero angular momentum. We study the structure of the rate of variation of the atomic energy. The intention is to clarify in a quantitative way the effect of the distinguished contributions of vacuum fluctuations and radiation reaction on spontaneous excitation and on spontaneous emission of atoms. In particular, we are interested in the comprehension of the combined action of the different physical processes underlying the Hawking effect in the scenario of rotating black holes as well as the Unruh-Starobinskii effect. We demonstrate that, in the case of static atoms, spontaneous excitation is also connected with the Unruh-Starobinskii effect, but only in the case of the quantum field prepared in the Frolov-Thorne vacuum state. In addition, we show that, in the zero angular momentum observer’s perspective, the Boulware vacuum state contains an outward flux of particles as a consequence of the black-hole superradiance. The possible relevance of the findings in the present work is discussed.

Precision studies of scattering processes at colliders provide powerful indirect constraints on new physics. We study the helicity structure of scattering amplitudes in the standard model (SM) and in the context of an effective Lagrangian description of beyond-the-SM (BSM) dynamics. Our analysis reveals a novel set of helicity selection rules according to which, in the majority of $2\to 2$ scattering processes at high energy, the SM and the leading BSM effects do not interfere. In such situations, the naive expectation that dimension-6 operators represent the leading BSM contribution is compromised, as corrections from dimension-8 operators can become equally (if not more) important well within the validity of the effective field theory approach.