We show that certain general properties of threshold and joint resummations in Drell-Yan cross sections hold as well for their crossed analogs in semi-inclusive deep-inelastic scattering and double-inclusive leptonic annihilation. We show that all plus-distribution corrections near threshold have the same structure, and are determined to all logarithmic order by two anomalous dimensions, one of which is a generalization of the $D$-term previously derived in Drell-Yan. We also discuss the possibility of universality in power corrections implied by the resummation.

We study the hadronic decay modes $B^{\pm (0)}\to f_0(980)K^{\pm (0)}$, involving a scalar and a pseudoscalar meson in the final state. These decay modes are dominated by the loop induced $b\to s\overline{q}q(q=s,u,d)$ penguins along with a small $b\to u$ tree level transition (for $B^{+}\to f_0{K}^{+}$) and annihilation diagrams. Therefore, the standard model expectation of direct $CP$ violation is negligibly small and the mixing-induced $CP$ violation parameter in the mode $B^0\to f_0{K}_S$ is expected to give the same value of $\sin (2\beta )$, as extracted from $B^0\to J/\psi K_S$ but with opposite sign. Using the generalized factorization approach we find the direct $CP$ violation in the decay mode $B^{+}\to f_0{K}^{+}$ to be of the order of few percent. We then study the effect of the $R$-parity violating supersymmetric model and show that the direct $CP$ violating asymmetry in $B^{+}\to f_0(980)K^{+}$ could be as large as $\sim 80\%$ and the mixing-induced $CP$ asymmetry in $B^0\to f_0{K}_S$ (i.e., $-S_{f_0{K}_S}$) could deviate significantly from that of $\sin (2\beta {)}_{J/\psi K_S}$.

If the cosmic dark matter consists of weakly-interacting massive particles, these particles should be produced in reactions at the next generation of high-energy accelerators. Measurements at these accelerators can then be used to determine the microscopic properties of the dark matter. From this, we can predict the cosmic density, the annihilation cross sections, and the cross sections relevant to direct detection. In this paper, we present studies in supersymmetry models with neutralino dark matter that give quantitative estimates of the accuracy that can be expected. We show that these are well matched to the requirements of anticipated astrophysical observations of dark matter. The capabilities of the proposed International Linear Collider (ILC) are expected to play a particularly important role in this study.

We provide a method for obtaining simple models of supersymmetry breaking, with all small mass scales generated dynamically, and illustrate it with explicit examples. We start from models of perturbative supersymmetry breaking, such as O’Raifeartaigh and Fayet models, that would respect an $R$ symmetry if their small input parameters transformed as the superpotential does. By coupling the system to a pure supersymmetric Yang-Mills theory (or a more general supersymmetric gauge theory with dynamically small vacuum expectation values), these parameters are replaced by powers of its dynamical scale in a way that is naturally enforced by the symmetry. We show that supersymmetry breaking in these models may be straightforwardly mediated to the supersymmetric standard model, obtain complete models of direct gauge mediation, and comment on related model building strategies that arise in this simple framework.

If the standard model is valid up to scales near the Planck mass, and if the cosmological constant and Higgs mass parameters scan on a landscape of vacua, it is well-known that the observed orders of magnitude of these quantities can be understood from environmental selection for large scale structure and atoms. If in addition the Higgs quartic coupling scans, with a probability distribution peaked at low values, environmental selection for a phase having a scale of electroweak symmetry breaking much less than the Planck scale leads to a most probable Higgs mass of 115 GeV. While fluctuations below this are negligible, the upward fluctuation is $25/p\mathrm{GeV}$, where $p$ measures the strength of the peaking of the a priori distribution of the quartic coupling. There is an additional $\pm 6\mathrm{GeV}$ uncertainty from calculable higher loop effects, and also sensitivity to the experimental values of $m_t$ and ${\alpha }_s$. If the top Yukawa coupling also scans, the most probable top quark mass is predicted to lie in the range (172.4–176.9) GeV, providing the standard model is valid to at least ${10}^{17}\mathrm{GeV}$, with an additional uncertainty of $\pm 3\mathrm{GeV}$ from higher loops. The downward fluctuation is $35\mathrm{GeV}/\sqrt{p}$, suggesting that $p$ is sufficiently large to give a very precise Higgs mass prediction. While a high reheat temperature after inflation could raise the most probable value of the Higgs mass to 124 GeV, maintaining the successful top prediction suggests that reheating is limited to about ${10}^9\mathrm{GeV}$, and that the most probable value of the Higgs mass remains at 115 GeV. If all Yukawa couplings scan, then the $e$, $u$, $d$, and $t$ masses are understood to be outliers having extreme values induced by the pressures of strong environmental selection, while the $s$, $\mu$, $c$, $b$, $\tau$ Yukawa couplings span only 2 orders of magnitude, reflecting an a priori distribution peaked around ${10}^{-3}$. An interesting extension to neutrino masses and leptogenesis follows if right-handed neutrino masses scan, with a preference for larger values, and if $T_R$ and $T_{\max }$ scan with mild distributions. The broad order of magnitude of the light neutrino masses and the baryon asymmetry are correctly predicted, while the right-handed neutrino masses, the reheat temperature and the maximum temperature are all predicted to be of order ${10}^9\mathrm{GeV}$.

We reconsider the constraints on universal extra dimensions models arising from precision electroweak data. We take into account the subleading contributions from new physics (expressed in terms of the $X,Y,\dots$ variables), as well as two-loop corrections to the standard model $\rho$ parameter. For the case of one extra dimension, we obtain a lower bound on the inverse compactification scale $M=R^{-1}$ of 600 GeV (at 90% confidence level), with a Higgs mass of 115 GeV. However, in contradiction to recent claims, we find that this constraint is significantly relaxed with increasing Higgs mass, allowing for compactification scales as low as 300 GeV. LEP II data does not affect significantly these results.

For a large enough Schwarzschild black hole, the horizon is a region of space where gravitational forces are weak; yet it is also a region leading to numerous puzzles connected to stringy physics. In this work, we analyze the process of gravitational collapse and black hole formation in the context of light-cone M-theory. We find that, as a shell of matter contracts and is about to reveal a black hole horizon, it undergoes a thermodynamic phase transition. This involves the binding of D0 branes into D2’s, and the new phase leads to large membranes of the size of the horizon. These in turn can sustain their large size through back-reaction and the dielectric Myers effect—realizing the fuzzball proposal of Mathur and the Matrix black hole of M(atrix) theory. The physics responsible for this phenomenon lies in strongly coupled $2+1$ dimensional noncommutative dynamics. The phenomenon has a universal character and appears generic.

Motivated by the search for gravitational waves emitted by binary black holes, we investigate the gravitational radiation field of point particles with spins within the framework of the multipolar-post-Newtonian wave generation formalism. We compute: (i) the spin-orbit (SO) coupling effects in the binary’s mass and current quadrupole moments one post-Newtonian (1PN) order beyond the dominant effect, (ii) the SO contributions in the gravitational-wave energy flux, and (iii) the secular evolution of the binary’s orbital phase up to 2.5PN order. Crucial ingredients for obtaining the 2.5PN contribution in the orbital phase are the binary’s energy and the spin-precession equations, derived in paper I of this series. These results provide more accurate gravitational-wave templates to be used in the data analysis of rapidly rotating Kerr-type black-hole binaries with the ground-based detectors LIGO, Virgo, GEO 600, and TAMA300, and the space-based detector LISA.

We derive the equations of motion of spinning compact binaries including the spin-orbit (SO) coupling terms one post-Newtonian (PN) order beyond the leading-order effect. For black holes maximally spinning this corresponds to 2.5PN order. Our result for the equations of motion essentially confirms the previous result by Tagoshi, Ohashi, and Owen. We also compute the spin-orbit effects up to 2.5PN order in the conserved (Noetherian) integrals of motion, namely, the energy, the total angular momentum, the linear momentum, and the center-of-mass integral. We obtain the spin precession equations at 1PN order beyond the leading term, as well. Those results will be used in a future paper to derive the time evolution of the binary orbital phase, providing more accurate templates for LIGO-Virgo-LISA–type interferometric detectors.

The main objective of this paper is to study thermodynamics and stability of static electrically charged Born-Infeld black holes in AdS space in $D=4$. The Euclidean action for the grand canonical ensemble is computed with the appropriate boundary terms. The thermodynamical quantities such as the Gibbs free energy, entropy and specific heat of the black holes are derived from it. The global stability of black holes are studied in detail by studying the free energy for various potentials. For small values of the potential, we find that there is a Hawking-Page phase transition between a BIAdS black hole and the thermal-AdS space. For large potentials, the black hole phase is dominant and is preferred over the thermal-AdS space. Local stability is studied by computing the specific heat for constant potentials. The nonextreme black holes have two branches: small black holes are unstable and the large black holes are stable. The extreme black holes are shown to be stable both globally as well as locally. In addition to the thermodynamics, we also show that the phase structure relating the mass $M$ and the charge $Q$ of the black holes is similar to the liquid-gas-solid phase diagram.

We present effective gravitational equations at low energies in a $Z_2$-symmetric braneworld with the Gauss-Bonnet term. Our derivation is based on the geometrical projection approach, and we solve iteratively the bulk geometry using the gradient expansion scheme. Although the original field equations are quite complicated due to the presence of the Gauss-Bonnet term, our final result clearly has the form of the Einstein equations plus correction terms, which is simple enough to handle. As an application, we consider homogeneous and isotropic cosmology on the brane. We also comment on the holographic interpretation of bulk gravity in the Gauss-Bonnet braneworld.

The current authors have previously shown that inhomogeneous, but spherically symmetric universe models containing only matter can yield a very good fit to the SNIa data and the position of the first cosmic microwave background (CMB) peak. In this work we examine how far away from the center of inhomogeneity the observer can be located in these models and still fit the data well. Furthermore, we investigate whether such an off-center location can explain the observed alignment of the lowest multipoles of the CMB map. We find that the observer has to be located within a radius of $\sim 15\mathrm{Mpc}$ from the center for the induced dipole to be less than that observed by the COBE satellite. But for such small displacements from the center, the induced quadru- and octopoles turn out to be insufficiently large to explain the alignment.

The recombination history of the Universe provides a useful tool for constraining the annihilation of dark matter particles. Even a small fraction of dark matter particles annihilated during the cosmic dark age can provide sufficient energy to affect the ionization state of the baryonic gas. Although this effect is too small for neutralinos, lighter dark matter particle candidates, e.g. with mass of 1–100 MeV, which was proposed recently to explain the observed excess of positrons in the galactic center, may generate observable differences in the cosmic microwave background (CMB) temperature and polarization anisotropies. The annihilations at the era of recombination affects mainly the CMB anisotropy at small angular scales (large $\ell$), and is distinctively different from the effect of early reionization. We perform a multiparameter analysis of the CMB data, including both the Wilkinson Microwave Anisotropy Probe (WMAP) first year and three year data, and the ACBAR, Boomerang, CBI, and VSA data. Assuming that the observed excess of $e^{+}{e}^{-}$ pairs in the galactic center region is produced by dark matter annihilation, and that a sizable fraction of the energy produced in the annihilation is deposited in the baryonic gas during recombination, we obtain a 95% dark matter mass limit of $M<8\mathrm{MeV}$ with the current data set.

The interacting dark energy model with interaction term $Q={\lambda }_{m}H{\rho }_m+{\lambda }_{d}H{\rho }_d$ is considered. By studying the model near the transition time, in which the system crosses the $\omega =-1$ phantom divide line, the conditions needed to overcome the coincidence problem is investigated. The phantom model, as a candidate for dark energy, is considered, and for two specific examples, the quadratic and exponential phantom potentials, it is shown that it is possible the system crosses the $\omega =-1$ line, meanwhile the coincidence problem is alleviated, the two facts that have root in observations.

For a long time it has been known that the like-sign dilepton signature can help establish the existence of a gluino at the LHC. To unambiguously claim that we see a strongly interacting Majorana fermion—which we could call a gluino—we need to prove that it is indeed a fermion. We propose how to extract this information from a different gluino-decay cascade which is also used to measure its mass. Looking only at angular correlations we distinguish a universal extra dimensional interpretation assuming a bosonic heavy gluon from supersymmetry with a fermionic gluino. Assuming a supersymmetric interpretation, we show how the same angular correlations can be used to study the left-right nature of the sfermions appearing in the decay chain.

Antisymmetric tensor fields with chiral couplings to quarks and leptons may induce spontaneous electroweak symmetry breaking in a model without a fundamental Higgs scalar. No microscopic local mass term for the chiral tensors or chirons is allowed by the symmetries and our model exhibits only dimensionless couplings. However, the chiral couplings are asymptotically free and therefore generate a mass scale where they grow large. We argue that at this scale mass terms for the chiral tensor fields are generated nonperturbatively—the chirons appear as new massive spin-one particles. Furthermore a scalar top-antitop condensate forms, giving mass to the weak gauge bosons and fermions. In this scenario the longstanding gauge hierarchy problem finds a solution similar to the mass generation in QCD. We compute the general form of the effective action for the chiral tensors and sketch several possibilities of their detection at LHC or through precision tests of the electroweak standard model.

We study the angular distributions of the baryon-antibaryon low-mass enhancements in the three-body baryonic $B$ decays of $B\to p\overline{p}M$ ($M=K$ and $\pi$) in the framework of the perturbative QCD. By writing the most general forms for the transition form factors of $B\to p\overline{p}$, we find that the angular distribution asymmetry in $B^{-}\to p\overline{p}{K}^{-}$ measured by Belle Collaboration can be explained. We give a quantitative description on the Dalitz plot asymmetry in $B^{-}\to p\overline{p}{K}^{-}$ shown by BABAR Collaboration and demonstrate that it is equivalent to the angular asymmetry. In addition, we present our results on ${\overline{B}}^0\to p\overline{p}{K}_S$ and $B^{-}\to p\overline{p}{\pi }^{-}$ and we obtain that their angular asymmetries are $-0.35\pm 0.11$ and $0.45\pm 0.10$, respectively, which can be tested by the ongoing experiments at the $B$ factories.

We study the lepton-flavor-violating reaction ${\mu }^{+}{e}^{-}\to e^{+}{e}^{-}$ within two extensions of the standard model that include heavy neutrinos. The reaction is studied in the low energy limit in the form of muonium decay $M\to e^{+}{e}^{-}$ and in the high energy regime of a muon collider. The two theoretical models we consider are: model I, a typical seesaw model that violates lepton flavor and number by inclusion of extra right-handed neutrinos; and model II, a variant where lepton number is conserved and which includes extra right-handed as well as left-handed neutrinos, singlets under the gauge group. We find for muonium decay into $e^{+}{e}^{-}$ the extremely small result $Br(M\to e^{+}{e}^{-})<{10}^{-19}$ in both scenarios. Alternatively, for ${\mu }^{+}{e}^{-}$ collisions up to $\sqrt{s}\sim 50\mathrm{GeV}$, we find $\sigma ({\mu }^{+}{e}^{-}\to e^{+}{e}^{-})<{10}^{-5}\mathrm{fb}$, while for energies above the $W^{+}{W}^{-}$ threshold we find $\sigma ({\mu }^{+}{e}^{-}\to W^{+}{W}^{-})$ up to $\sim 1\mathrm{fb}$.

We report measurements of the inclusive electron momentum spectra in decays of charged and neutral $B$ mesons, and of the ratio of semileptonic branching fractions $\mathcal{B}(B^{+}\to Xe\nu )$ and $\mathcal{B}(B^0\to Xe\nu )$. These were performed on a sample of $231\times {10}^6$ $B\overline{B}$ events recorded with the BABAR detector at the ${\rm Y}(4S)$ resonance. Events are selected by fully reconstructing a hadronic decay of one $B$ meson and identifying an electron among the decay products of the recoiling $\overline{B}$ meson. We obtain $\mathcal{B}(B^{+}\to Xe\nu )/\mathcal{B}(B^0\to Xe\nu )=1.074\pm {0.041}_{(\mathrm{stat})}\pm {0.026}_{(\mathrm{syst})}$.