Short baseline neutrino oscillation experiments have shown hints of the existence of additional sterile neutrinos in the eV mass range. Such sterile neutrinos are incompatible with cosmology because they suppress structure formation unless they can be prevented from thermalizing in the early Universe or removed by subsequent decay or annihilation. Here, we present a novel scenario in which both sterile neutrinos and dark matter are coupled to a new, light pseudoscalar. This can prevent thermalization of sterile neutrinos and make dark matter sufficiently self-interacting to have an impact on galactic dynamics and possibly resolve some of the known problems with the standard cold dark matter scenario. Even more importantly it leads to a strongly self-interacting plasma of sterile neutrinos and pseudoscalars at late times and provides an excellent fit to cosmic microwave background data. The usual cosmological neutrino mass problem is avoided by sterile neutrino annihilation to pseudoscalars. The preferred value of $H_0$ is substantially higher than in standard $\mathrm{\Lambda }\mathrm{CDM}$ (lambda cold dark matter) and in much better agreement with local measurements.

The electrical laws and Carnot cycle of isolated horizons (IH) are investigated in this paper. We establish Ohm’s law and Joule’s law of isolated horizons and find that the conceptual picture of black holes (membrane paradigm) can also apply to this kind of quasilocal black holes. We also investigate the geometrical properties near nonrotating IHs and find that under the first-order approximation of $r$, there exist a Killing vector $\frac{\partial }{\partial u}$ and a Hamiltonian conjugate to it, so this vector can be thought to be a physical observer. We calculate the energy as measured at infinity of a particle at rest outside a nonrotating IH, and we use this result to construct a reversible Carnot cycle with the isolated horizon as a cold reservoir, which confirms the thermodynamic nature of isolated horizons.

We investigate general optical interferometry in stationary spacetimes focusing on quantum-optical experiments in near-Earth environments. We provide a rigorous expression for the gravitationally induced phase difference and adapt the parametrized post-Newtonian formalism for calculations of polarization rotation. We investigate two optical versions of the Colella-Overhauser-Werner experiment and show that the phase difference is independent of the post-Newtonian parameter $\gamma$, making it a possible candidate for an optical test of the Einstein equivalence principle. Polarization rotation provides an example of the quantum clock variable and, while related to the optical Lense-Thirring effects, shows a qualitatively different behavior from them.

The presence of charged scalars is almost inevitable in most of the beyond standard model scenarios. They are expected to be detected easily if they are there due to their electromagnetic charge. These charged scalars can be produced at the LHC and their decays may lead to interesting signals—multilepton final states, displaced vertices, etc. These charged particles also play crucial roles in low energy rare processes. Thus apart from the collider searches in low energy rare processes their presence can be smelled. Here, we have noted the impact of doubly charged scalars in rare meson decays. As the mesons are lighter these heavy scalars always appear off shell. Due to their off-shell structure the phase space is relatively complicated to deal with. In this paper we have supplemented a general proposal to compute these decays that involve off-shell doubly charged scalars. We have argued that our prescription can be used for any process involving off-shell heavy scalars. Using the prescribed method we have computed two possible meson decays: $M^{\pm }\to l_i^{\pm }{l}_j^{\pm }{M}^{\prime \mp }$, $M^{\pm }\to l_i^{\pm }{l}_j^{\pm }{l}_m^{\mp }{l}_n^{\mp }{M}^{\prime \pm }$. We have also estimated the numerical values of the branching ratios in different channels for different charged mesons.

Anticipating that a dijet resonance could be discovered at the 14 TeV LHC, we present two different strategies to reveal the nature of such a particle; in particular to discern whether it is a quark-antiquark ($q\overline{q}$), quark-gluon ($qg$), or gluon-gluon ($gg$) resonance. The first method relies on the color discriminant variable, which can be calculated at the LHC from the measurements of the dijet signal cross section, the resonance mass, and the resonance width. Including estimated statistical uncertainties and experimental resolution, we show that a $qg$ excited quark resonance can be efficiently distinguished from either a $\overline{q}q$ coloron or a $gg$ color-octet scalar using the color discriminant variable at LHC-14. The second strategy is based on the study of the energy profiles of the two leading jets in the dijet channel. Including statistical uncertainties in the signal and the QCD backgrounds, we show that one can distinguish, in a model-independent way, between $gg$, $qg$, and $q\overline{q}$ resonances; an evaluation of systematic uncertainties in the measurement of the jet energy profile will require a detailed detector study once sufficient 14 TeV dijet data are in hand.

We consider the case that the $\mu -e$ conversion signal is discovered but other charged lepton flavor violating (cLFV) processes will never be found. In such a case, we need other approaches to confirm the $\mu -e$ conversion and its underlying physics without conventional cLFV searches. We study R-parity violating (RPV) SUSY models as a benchmark. We briefly review that our interesting case is realized in RPV SUSY models with reasonable settings in light of current theoretical and experimental status. We focus on the exotic collider signatures at the LHC ($pp\to {\mu }^{-}{e}^{+}$ and $pp\to jj$) as the other approaches. We show the correlations between the branching ratio of the $\mu -e$ conversion process and cross sections of these processes. It is the first time that these correlations have been graphically shown. We exhibit the RPV parameter dependence of the branching ratio and the cross sections and discuss the feasibility of determining the parameters.

We consider “double-winding” Wilson loops in SU(2) gauge theory. These are contours which wind once around a loop $C_1$ and once around a loop $C_2$, where the two co-planar loops share one point in common, and where $C_1$ lies entirely in (or is displaced slightly from) the minimal area of $C_2$. We discuss the expectation value of such double-winding loops in Abelian confinement pictures, where the spatial distribution of confining Abelian fields is controlled by either a monopole Coulomb gas, a caloron ensemble, or a dual Abelian Higgs model, and argue that in such models an exponential falloff in the sum of areas $A_1+A_2$ is expected. In contrast, in a center vortex model of confinement, the behavior is an exponential falloff in the difference of areas $A_2-A_1$. We compute such double-winding loops by lattice Monte Carlo simulation, and find that the area law falloff follows a difference-in-areas law. The conclusion is that even if confining gluonic field fluctuations are, in some gauge, mainly Abelian in character, the spatial distribution of those Abelian fields cannot be the distribution predicted by the simple monopole gas, caloron ensemble, or dual Abelian Higgs actions, which have been used in the past to explain the area law falloff of Wilson loops.

Jet vetoes are a prominent part of the signal selection in various analyses at the LHC. We discuss jet vetoes for which the transverse momentum of a jet is weighted by a smooth function of the jet rapidity. With a suitable choice of the rapidity-weighting function, such jet-veto variables can be factorized and resummed allowing for precise theory predictions. They thus provide a complementary way to divide phase space into exclusive jet bins. In particular, they provide a natural and theoretically clean way to implement a tight veto on central jets with the veto constraint getting looser for jets at increasingly forward rapidities. We mainly focus our discussion on the 0-jet case in color-singlet processes, using Higgs production through gluon fusion as a concrete example. For one of our jet-veto variables we compare the resummed theory prediction at ${\mathrm{NLL}}^{\prime }+\mathrm{N}\mathrm{L}\mathrm{O}$ order with the recent differential cross-section measurement by the ATLAS experiment in the $H\to \gamma \gamma$ channel, finding good agreement. We also propose that these jet-veto variables can be measured and tested against theory predictions in other Standard Model processes, such as Drell-Yan, diphoton, and weak diboson production.

The asymmetries in the forward region production cross section of ${\mathrm{\Lambda }}_c^{+}/{\mathrm{\Lambda }}_c^{-}$ and ${\mathrm{\Lambda }}_b^0/{\overline{\mathrm{\Lambda }}}_b^0$ are predicted using the heavy quark recombination mechanism for $pp$ collisions at 7 TeV and 14 TeV. Using nonperturbative parameters determined from various previous experiments, we find that $A_p({\mathrm{\Lambda }}_c^{+}/{\mathrm{\Lambda }}_c^{-})\sim 1–2\%$ in the region $2<y<5$ and $2\mathrm{GeV}<p_T<20\mathrm{GeV}$ and $A_p({\mathrm{\Lambda }}_b^0/{\overline{\mathrm{\Lambda }}}_b^0)\sim 1–3\%$ in the region $2<y<5$ and $5\mathrm{GeV}<p_T<20\mathrm{GeV}$. The differential distributions of $A_p$ are significant at the high-rapidity and low-$p_T$ ends ($\sim 2–15\%$). Sensitivity of the integrated $A_p$ on the upper rapidity cut and lower $p_T$ cut is discussed.

Recently, Kajiyama, Okada and Yagyu proposed an electron/muon specific two Higgs doublet model. In this model, an $S_3$ symmetry suppresses flavor-changing neutral currents instead of a $Z_2$ symmetry. In the “Type I” version of the model, the heavy Higgs bosons have a greatly enhanced coupling to electrons and muons. Kajiyama, Okada and Yagyu studied the phenomenology of the heavy Higgs bosons at the LHC. In this paper, the phenomenology at electron-positron colliders is studied. For the heavy Higgs mass range between 150 and 210 GeV, bounds from Large Electron Positron (LEP-200) Collider are stronger than those from the LHC. The model allows for the interesting possibility that muon pair production at the International Linear Collider can be mediated by s-channel Higgs exchange. This requires an energy scan. The scanning rate and necessary resolution are discussed.

In the experiment with the SND detector at the VEPP-2000 $e^{+}{e}^{-}$ collider the cross section for the process $e^{+}{e}^{-}\to \eta {\pi }^{+}{\pi }^{-}$ has been measured in the center-of-mass energy range from 1.22 to 2.00 GeV. Obtained results are in agreement with previous measurements and have better accuracy. The energy dependence of the $e^{+}{e}^{-}\to \eta {\pi }^{+}{\pi }^{-}$ cross section has been fitted with the vector-meson dominance model. From this fit the product of the branching fractions $B(\rho (1450)\to \eta {\pi }^{+}{\pi }^{-})B(\rho (1450)\to e^{+}{e}^{-})$ has been extracted and compared with the same products for $\rho (1450)\to \omega {\pi }^0$ and $\rho (1450)\to {\pi }^{+}{\pi }^{-}$ decays. The obtained cross section data have been also used to test the conservation of vector current hypothesis.

A search is performed for long-lived particles that decay into final states that include a pair of electrons or a pair of muons. The experimental signature is a distinctive topology consisting of a pair of charged leptons originating from a displaced secondary vertex. Events corresponding to an integrated luminosity of $19.6(20.5){\mathrm{fb}}^{-1}$ in the electron (muon) channel were collected with the CMS detector at the CERN LHC in proton-proton collisions at $\sqrt{s}=8\mathrm{TeV}$. No significant excess is observed above standard model expectations. Upper limits on the product of the cross section and branching fraction of such a signal are presented as a function of the long-lived particle’s mean proper decay length. The limits are presented in an approximately model-independent way, allowing them to be applied to a wide class of models yielding the above topology. Over much of the investigated parameter space, the limits obtained are the most stringent to date. In the specific case of a model in which a Higgs boson in the mass range $125–1000\mathrm{GeV}/c^2$ decays into a pair of long-lived neutral bosons in the mass range $20–350\mathrm{GeV}/c^2$, each of which can then decay to dileptons, the upper limits obtained are typically in the range 0.2–10 fb for mean proper decay lengths of the long-lived particles in the range 0.01–100 cm. In the case of the lowest Higgs mass considered ($125\mathrm{GeV}/c^2$), the limits are in the range 2–50 fb. These limits are sensitive to Higgs boson branching fractions as low as $10^{-4}$.

We present the electromagnetic gauge field interpolation between the instant form and the front form of the relativistic Hamiltonian dynamics and extend our interpolation of the scattering amplitude presented in the simple scalar field theory to the case of the electromagnetic gauge field theory with the scalar fermion fields known as the scalar quantum electrodynamics (sQED) theory. We find that the Coulomb gauge in the instant form dynamics and the light-front gauge in the front form dynamics, or the light-front dynamics (LFD), are naturally linked by the unified general physical gauge that interpolates between these two forms of dynamics and derive the spin-1 polarization vector for the photon that can be generally applicable for any interpolation angle. The corresponding photon propagator for an arbitrary interpolation angle is found and examined in terms of the gauge field polarization and the interpolating time ordering. Using these results, we calculate the lowest-order scattering processes for an arbitrary interpolation angle in sQED. We provide an example of breaking the reflection symmetry under the longitudinal boost, $P^z\leftrightarrow -P^z$, for the time-ordered scattering amplitude in any interpolating dynamics except the LFD and clarify the confusion in the prevailing notion of the equivalence between the infinite momentum frame and the LFD. The particular correlation found in our previous analysis of the scattering amplitude in the simple scalar field theory, coined as the J-shaped correlation, between the total momentum of the system and the interpolation angle persists in the present analysis of the sQED scattering amplitude. We discuss the singular behavior of this correlation in conjunction with the zero-mode issue in the LFD.

In contrast to the three-dimensional case, different approaches for deriving the gravitational corrections to the Heisenberg uncertainty relation do not lead to the unique result, whereas additional spatial dimensions are present in the theory. We suggest taking logarithmic corrections to the black hole entropy, which has recently been proved in both string theory and loop quantum gravity to persist in the presence of additional spatial dimensions, as a point of entry for identifying the modified Heisenberg-Weyl algebra. We then use a particular Hilbert-space representation for such a quantum mechanics to construct the correspondingly modified field theory and address some phenomenological issues following from it. Some subtleties arising at the second quantization level are clearly pointed out. Solving the field operator to the first order in the deformation parameter and defining the modified wave function for a free particle, we discuss the possible phenomenological implications for the black hole evaporation. Putting aside modifications arising at the second quantization level, we address the corrections to the gravitational potential due to a modified propagator (backreaction on gravity) and see that a correspondingly modified Schwarzschild-Tangherlini space-time reproduces the disappearance of the horizon and the vanishing of the surface gravity when the black hole mass approaches the quantum gravity scale. This result points to the existence of zero-temperature black hole remnants.

Inspired by the study of mild transient reductions in the speed of sound of the adiabatic mode during inflation, we search for a primordial localized feature imprinted in cosmic microwave background and large-scale structure formation observables. We find some common oscillatory patterns both in the Planck CMB temperature-temperature power spectrum and the WiggleZ galaxy spectrum. By performing independent searches with these two data sets, we find a coincidence in the most significant mode previously found by Achúcarro et al. in 2013 by using only Planck data. Furthermore, the joint data analysis shows that the oscillation frequency of the feature gets better constrained, and the amplitude marginally deviates from zero, unlike what was observed using only Planck data. Besides the parameter estimation, we also discuss the Bayesian evidence. The addition of WiggleZ data mildly enhances the significance of the best mode found in the Planck data.

In this paper, we show that the $\gamma +\text{jet}$ invariant mass distribution in proton-proton collisions at the LHC is significantly sensitive to the quark chromomagnetic ($\kappa$) and chromoelectric ($\tilde{\kappa }$) dipole moments. It is shown that the presence of $\kappa$ or $\tilde{\kappa }$ leads to an increment of the cross section of the $\gamma +\text{jet}$ process, in particular, in the tail of the $\gamma +\text{jet}$ invariant mass distribution. Using the measured $\gamma +\text{jet}$ invariant mass distribution by the CMS experiment at the center-of-mass energy of 8 TeV, we derive bounds on the quark chromoelectric and chromomagnetic dipole moments. In the extraction of the limits, we consider both theoretical and systematic uncertainties. The uncertainties originating from variation of the renormalization or factorization scales and the choice of proton parton distribution functions are taken into account as a function of the $\gamma +\text{jet}$ invariant mass. We exclude $\kappa$ or $\tilde{\kappa }$ above $10^{-5}$ at 95% confidence level. This is the most stringent direct upper limit on $\kappa$ or $\tilde{\kappa }$.

We present a lattice QCD calculation of the pseudoscalar decay constants $f_K$, $f_D$ and $f_{D_s}$ performed using the gauge configurations produced by the European Twisted Mass Collaboration with $N_f=2+1+1$ dynamical quarks, which include in the sea, besides two light mass degenerate quarks, also the strange and charm quarks with masses close to their values in the real world. The simulations are based on a unitary setup for the two light mass-degenerate quarks and on a mixed action approach for the strange and charm quarks. We use data simulated at three different values of the lattice spacing in the range $0.06–0.09\mathrm{fm}$ and at pion masses in the range $210–450\mathrm{MeV}$. Our main results are $f_{K^{+}}/f_{{\pi }^{+}}=1.184(16)$, $f_{K^{+}}=154.4(2.0)\mathrm{MeV}$, which incorporate the leading strong isospin breaking correction due to the up and down quark mass difference, and $f_K=155.0(1.9)\mathrm{MeV}$, $f_D=207.4(3.8)\mathrm{MeV}$, $f_{D_s}=247.2(4.1)\mathrm{MeV}$, $f_{D_s}/f_D=1.192(22)$ and $(f_{D_s}/f_D)/(f_K/f_{\pi })=1.003(14)$ obtained in the isospin symmetric limit of QCD. Combined with the experimental measurements of the leptonic decay rates of kaon, pion, $D$ and $D_s$ mesons our results lead to the following determination of the Cabibbo-Kobayashi-Maskawa (CKM) matrix elements: $|V_{us}|=0.2269(29)$, $|V_{cd}|=0.2221(67)$ and $|V_{cs}|=1.014(24)$. Using the latest value of $|V_{ud}|$ from superallowed nuclear $\beta$ decays the unitarity of the first row of the CKM matrix is fulfilled at the per mill level.