Recently, the ATLAS and CMS collaborations reported exciting hints of a standard model-like Higgs boson with a mass around 125 GeV. Such a Higgs boson mass can be easily obtained in the minimal supersymmetric standard model based on the “pure gravity mediation model” where the sfermion masses and the Higgs mass parameters are in the tens to hundreds TeV range, while the gauginos are in the hundreds GeV to TeV range. In this paper, we discuss details of the gaugino mass spectrum in the pure gravity mediation model. We also discuss the signals of the model at current and future experiments such as cosmic-ray observations and the LHC experiments. In particular, we show that the parameter space which is consistent with the thermal leptogenesis can be fully surveyed experimentally in the foreseeable future.

Using data from $p\overline{p}$ collisions at $\sqrt{s}=1.96\mathrm{TeV}$ recorded by the CDF II detector at the Fermilab Tevatron, we present improved measurements of the masses and first measurements of natural widths of the four bottom baryon resonance states ${\Sigma }_b^{+}$, ${\Sigma }_b^{*+}$ and ${\Sigma }_b^{-}$, ${\Sigma }_b^{*-}$. These states are fully reconstructed in their decay modes to ${\Lambda }_b^0{\pi }^{\pm }$ where ${\Lambda }_b^0\to {\Lambda }_c^{+}{\pi }^{-}$ with ${\Lambda }_c^{+}\to p{K}^{-}{\pi }^{+}$. The analysis is based on a data sample corresponding to an integrated luminosity of $6.0{\mathrm{fb}}^{-1}$ collected by an online event selection based on tracks displaced from the $p\overline{p}$ interaction point.

We report measurements of the charge-separated $W^{+(-)}\to e^{+(-)}+{\nu }_e({\overline{\nu }}_e)$ and $Z/{\gamma }^{*}\to e^{+}{e}^{-}$ production cross sections at mid-rapidity in proton-proton collisions at $\sqrt{s}=500\mathrm{GeV}$. These results are based on $13.2{\mathrm{pb}}^{-1}$ of data recorded in 2009 by the STAR detector at RHIC. Production cross sections for $W$ bosons that decay via the $e\nu$ channel were measured to be $\sigma (pp\to W^{+}X)·\mathrm{BR}(W^{+}\to e^{+}{\nu }_e)=117.3\pm 5.9(\mathrm{stat})\pm 6.2(\mathrm{syst})\pm 15.2(\mathrm{lumi})\mathrm{pb}$, and $\sigma (pp\to W^{-}X)·\mathrm{BR}(W^{-}\to e^{-}{\overline{\nu }}_e)=43.3\pm 4.6(\mathrm{stat})\pm 3.4(\mathrm{syst})\pm 5.6(\mathrm{lumi})\mathrm{pb}$. For $Z/{\gamma }^{*}$ production, $\sigma (pp\to Z/{\gamma }^{*}X)·\mathrm{BR}(Z/{\gamma }^{*}\to e^{+}{e}^{-})=7.7\pm 2.1(\mathrm{stat}{)}_{-0.9}^{+0.5}(\mathrm{syst})\pm 1.0(\mathrm{lumi})\mathrm{pb}$ was measured for di-lepton invariant masses $m_{e^{+}{e}^{-}}$ between 70 and $110\mathrm{GeV}/c^2$. First measurements of the $W$ cross section ratio, $\sigma (pp\to W^{+}X)/\sigma (pp\to W^{-}X)$, at $\sqrt{s}=500\mathrm{GeV}$ are also reported. Theoretical predictions, calculated using recent parton distribution functions, are found to agree with the measured cross sections.

The AdS/CFT correspondence relates Wilson loops in $\mathcal{N}=4$ super Yang-Mills theory to minimal area surfaces in ${\mathrm{AdS}}_5$ space. In this paper we consider the case of Euclidean flat Wilson loops, which are related to minimal area surfaces in Euclidean ${\mathrm{AdS}}_3$ space. Using known mathematical results for such minimal area surfaces, we describe an infinite parameter family of analytic solutions for closed Wilson loops. The solutions are given in terms of Riemann theta functions, and the validity of the equations of motion is proven based on the trisecant identity. The world sheet has the topology of a disk, and the renormalized area is written as a finite, one-dimensional contour integral over the world-sheet boundary. An example is discussed in detail with plots of the corresponding surfaces. Further, for each Wilson loops we explicitly construct a one parameter family of deformations that preserve the area. The parameter is the so-called spectral parameter.

Black hole thermodynamics suggests that a black hole should have an entropy given by a quarter of the area of its horizon. Earlier calculations in U(1) loop quantum gravity have led to a dominant term proportional to the area, but there was a correction involving the logarithm of the area. We find however that SU(2) loop quantum gravity can provide an entropy that is strictly proportional to the area as expected from black hole thermodynamics.

Compact binary coalescences, such as binary neutron stars or black holes, are among the most promising candidate sources for the current and future terrestrial gravitational-wave detectors. While such sources are best searched using matched template techniques and chirp template banks, integrating chirp signals from binaries over the entire universe also leads to a gravitational-wave background (GWB). In this paper we systematically scan the parameter space for the binary coalescence GWB models, taking into account uncertainties in the star formation rate and in the delay time between the formation and coalescence of the binary, and we compare the computed GWB to the expected sensitivities of the second and third generation gravitational-wave detector networks. We find that second generation detectors are likely to detect the binary coalescence GWB, while the third generation detectors will probe most of the available parameter space. The binary coalescence GWB will, in fact, be a foreground for the third generation detectors, potentially masking the GWB background due to cosmological sources. Accessing the cosmological GWB with third generation detectors will therefore require identification and subtraction of all inspiral signals from all binaries in the detectors’ frequency band.

We study the effect of weak lensing by cosmic (super-)strings on the anisotropies of cosmic microwave background (CMB). In developing a method to calculate the lensing convergence field due to strings, and thereby temperature and polarization angular power spectra of CMB, we clarify how the nature of strings, characterized by the intercommuting probability, can influence these CMB anisotropies. Assuming that the power spectrum is dominated by Poisson-distributed string segments, we find that the convergence spectrum peaks at low multipoles and is mostly contributed from strings located at relatively low redshifts. As the intercommuting probability decreases, the spectra of the convergence and hence the lensed temperature and polarizations are gained because the number density of string segments becomes larger. An observationally important feature of the string-induced CMB polarizations is that the string-lensed spectra decay more slowly on small scales compared with primordial scalar perturbations from standard inflation.

A generic prediction of string theory is the existence of many axion fields. It has recently been argued that many of these fields should be light and, like the well-known QCD axion, lead to observable cosmological consequences. In this paper, we study in detail the effect of the so-called string axiverse on large-scale structure, focusing on the morphology and evolution of density perturbations, anisotropies in the cosmic microwave background, and weak gravitational lensing of distant galaxies. We quantify specific effects that will arise from the presence of the axionic fields and highlight possible degeneracies that may arise in the presence of massive neutrinos. We take particular care understanding the different physical effects and scales that come into play. We then forecast how the string axiverse may be constrained and show that with a combination of different observations, it should be possible to detect a fraction of ultralight axions to dark matter of a few percent.

Our current understanding of the Universe depends on the interplay of several distinct matter components, which interact mainly through gravity, and electromagnetic radiation. The nature of the different components, and possible interactions, tends to be based on the notion of coupled perfect fluids (or scalar fields). This approach is somewhat naive, especially if one wants to be able to consider issues involving heat flow, dissipative mechanisms, or Bose-Einstein condensation of dark matter. We argue that a more natural starting point would be the multipurpose variational relativistic multifluid system that has so far mainly been applied to neutron star astrophysics. As an illustration of the fundamental principles involved, we develop the formalism for determining the nonlinear cosmological solutions to the Einstein equations for a general relativistic two-fluid model for a coupled system of matter (nonzero rest mass) and radiation (zero rest mass). The two fluids are allowed to interpenetrate and exhibit a relative flow with respect to each other, implying, in general, an anisotropic Universe. We use initial conditions such that the massless fluid flux dominates early on so that the situation is effectively that of a single-fluid and one has the usual Friedmann-Lemaître-Robertson-Walker spacetime. We find that there is a Bianchi I transition epoch out of which the matter flux dominates. The situation is then effectively that of a single fluid and the spacetime evolves towards the Friedmann-Lemaître-Robertson-Walker form. Such a transition opens up the possibility of imprinting observable consequences at the specific scale corresponding to the transition time.

P-vortices, in an SU($N$) lattice gauge theory, are excitations on the center-projected $Z_N$ lattice. We study the ratio of expectation values of SU(2) Wilson loops, on the unprojected lattice, linked to a single P-vortex, to that of Wilson loops which are not linked to any P-vortices. When these ratios are plotted versus loop area in physical units, for a range of lattice couplings, it is found that the points fall approximately on a single curve, consistent with scaling. We also find that the ratios are rather insensitive to the point where the minimal area of the loop is pierced by the P-vortex.

Proton decay is a generic prediction of GUT models and is therefore an important channel to detect the existence of unification or to set limits on GUT models. Current bounds on the proton lifetime are around ${10}^{33}\mathrm{years}$, which sets stringent limits on the GUT scale. These limits are obtained under “reasonable” assumptions about the size of the hadronic matrix elements. In this paper we present a nonperturbative calculation of the hadronic matrix elements within the chiral bag model of the proton. We argue that there is an exponential suppression of the matrix elements, due to nonperturbative QCD, that stifles proton decay by orders of magnitude—potentially $\mathcal{O}({10}^{-10})$. This suppression is present for small quark masses and is due to the chiral symmetry breaking of QCD. Such a suppression has clear implications for GUT models and could resuscitate several scenarios.

We compute the dark matter relic densities of neutralinos and axions in a supersymmetric model with a gauged anomalous U(1) symmetry. The model is a variant of the USSM [the U(1) extended NMSSM], containing an extra U(1) symmetry and an extra singlet in the superpotential with respect to the MSSM, where gauge invariance is restored by Peccei-Quinn interactions using a Stückelberg multiplet. This approach introduces an axion ($\mathrm{Im}b$) and a saxion ($\mathrm{Re}b$) in the spectrum and generates an axino component for the neutralino. The Stückelberg axion ($\mathrm{Im}b$) develops a physical component (the gauged axion) after electroweak symmetry breaking. We classify all the interactions of the Lagrangian and perform a complete simulation study of the spectrum, determining the neutralino relic densities using micrOMEGAs. We discuss the phenomenological implications of the model analyzing mass values for the axion from the milli-eV to the MeV region. These depend sensitively on the value of $\tan \beta$. The possible scenarios that we analyze are significantly constrained by a combination of WMAP data, the exclusion limits from direct axion searches, and the veto on late entropy release at the time of nucleosynthesis.

In the paper Phys. Rev. D 83, 054008 (2011) we constructed the $\pi \pi$ scattering amplitude $T_0^0$ with regular analytical properties in the $s$ complex plane, describing both experimental data and the results based on chiral expansion and Roy equations. Now the results obtained during development of our work are presented. We dwell on questions dealing with the low $\sigma -f_0$ mixing, inelasticity description and the kaon loop model for $\varphi \to \gamma (\sigma +f_0)$ reaction, and show a number of new fits. In particular, we show that the minimization of the $\sigma -f_0$ mixing results in the four-quark scenario for light scalars: the $\sigma$(600) coupling with the $K\overline{K}$ channel is suppressed relatively to the coupling with the $\pi \pi$ channel, and the $f_0$(980) coupling with the $\pi \pi$ channel is suppressed relatively to the coupling with the $K\overline{K}$ channel. The correct analytical properties of the $\pi \pi$ scattering amplitude are reached with the help of rather complicated background function. We also suggest much more simple background parameterization, practically preserving the resonance features, which is comfortable for experimental data analysis, but allows to describe the results based on chiral expansion and Roy equations only on the real $s$ axis.

There has been a recent controversial claim that the standard result on the Higgs to two photon decay rate is incorrect, with the use of dimensional regularization fingered as the alleged culprit. Given the great importance of the $H\to \gamma \gamma$ process as a possible standard model Higgs discovery channel at the LHC if the Higgs mass is light, it is critical to find a way to check the correctness of the results of dimensional regularization for this process. Here we report the results of a perturbative calculation of the $H\to \gamma \gamma$ decay amplitude using a spacetime lattice as a UV regulator, which is the only known gauge-invariant regulator for non-Abelian gauge theories other than dimensional regularization. We find that the decay amplitude calculated using lattice-regularized perturbation theory is consistent to very high statistical accuracy with the decay amplitude obtained using dimensional regularization.

It is shown that possible observation by direct kinematical means of a neutrino moving faster than the conventional velocity of light, $c$ could be an indication of dark matter bathing the Earth. In such a situation, the conventional velocity of light would be interpreted as the velocity of light in dark matter. The larger “true velocity” of light in vacuum is designated, $c_t$.

This paper, together with a preceding paper, questions the so-called “LSND anomaly”: a $3.8\sigma$ excess of ${\overline{\nu }}_{\mathrm{e}}$ interactions over standard backgrounds, observed by the LSND Collaboration in a beam dump experiment with 800 MeV protons. That excess has been interpreted as evidence for the ${\overline{\nu }}_{\mu }\to {\overline{\nu }}_{\mathrm{e}}$ oscillation in the $\Delta m^2$ range from $0.2{\mathrm{eV}}^2$ to $2{\mathrm{eV}}^2$. Such a $\Delta m^2$ range is incompatible with the widely accepted model of oscillations between three light neutrino species and would require the existence of at least one light “sterile” neutrino. In a preceding paper, it was concluded that the estimates of standard backgrounds must be significantly increased. In this paper, the LSND Collaboration’s estimate of the number of ${\overline{\nu }}_{\mathrm{e}}$ interactions followed by neutron capture, and of its error, is questioned. The overall conclusion is that the significance of the “LSND anomaly” is not larger than $2.3\sigma$.

This paper, together with a subsequent paper, questions the so-called “LSND anomaly”: a $3.8\sigma$ excess of ${\overline{\nu }}_e$ interactions over standard backgrounds, observed by the LSND Collaboration in a beam dump experiment with 800 MeV protons. That excess has been interpreted as evidence for the ${\overline{\nu }}_{\mu }\to {\overline{\nu }}_e$ oscillation in the $\Delta m^2$ range from $0.2{\mathrm{eV}}^2$ to $2{\mathrm{eV}}^2$. Such a $\Delta m^2$ range is incompatible with the widely accepted model of oscillations between three light neutrino species and would require the existence of at least one light “sterile” neutrino. In this paper, new data on pion production by protons on nuclei are presented, and four decades old data on pion production by neutrons on nuclei are recalled, that together increase significantly the estimates of standard backgrounds in the LSND experiment, and decrease the significance of the “LSND anomaly” from $3.8\sigma$ to $2.9\sigma$. In a subsequent paper, in addition the LSND Collaboration’s data analysis will be questioned, rendering a further reduction of the significance of the “LSND anomaly”.

We study reduced matrix models obtained by the dimensional reduction of $\mathcal{N}=2$ quiver Chern-Simons theories on $S^3$ to zero dimension and show that if a reduced model is expanded around a particular multiple fuzzy sphere background, it becomes equivalent to the original theory on $S^3$ in the large-$N$ limit. This is regarded as a novel large-$N$ reduction on a curved space $S^3$. We perform the localization method to the reduced model and compute the free energy and the vacuum expectation value of a BPS Wilson loop operator. In the large-$N$ limit, we find an exact agreement between these results and those in the original theory on $S^3$.

We propose an open quantum systems approach to the physics of heavy quarkonia in a thermal medium, based on stochastic quantum evolution. This description emphasizes the importance of collisions with the environment and focuses on the concept of spatial decoherence of the heavy quarkonium wave function. It is shown how to determine the parameters of the dynamical evolution, i.e. the real potential and the noise strength, from a comparison with quantities to be obtained from lattice QCD. Furthermore, the imaginary part of the lattice QCD heavy quark potential is found to be naturally related to the strength of the noise correlations. We discuss the time evolution of $Q\overline{Q}$ analytically in a limiting scenario for the spatial decoherence and provide a qualitative one-dimensional numerical simulation of the real-time dynamics.