118487966
Detecting interactions between dark matter and photons at high energy e(+)e(-) colliders
We investigate the sensitivity to the effective operators describing interactions between dark matter particles and photons at future high energy e+e(-) colliders via the gamma + is not an element of channel. Such operators could be useful to interpret the potential gamma-ray line signature observed by the Fermi-LAT. We find that these operators can be further tested at e(+)e(-) colliders by using either unpolarized or polarized beams. We also derive a general unitarity condition for 2 -> n processes and apply it to the dark matter production process e(+)e(-) -> chi chi gamma.
118840081
Constraining the interaction strength between dark matter and visible matter: II. Scalar, vector and spin-3/2 dark matter
We investigate the constraints on the scalar, vector and spin-3/2 dark matter interaction with the standard model particles, from the observations of dark matter relic density, the direct detection experiments of COMS and XENON, and the indirect detection of the (p) over bar /p ratio by PAMELA. A model independent way is adopted by constructing general 4-particle operators up to dimension 6 for the effective interaction between dark matter and standard model particles. We find that the constraints from different experiments are complementary with each other. Comparison among these constraints may exclude some effective models of dark matter and limit some parameters of others. The spin-independent direct detection gives strong constraints for some operators, while the indirect detection of (p) over bar /p data can be more sensitive than direct detection or relic density for light dark matter (whose mass less than or similar to 70 GeV) in some cases. The constraints on some operators for spin-3/2 dark matter are shown to be similar to those on their analogous operators for Dirac fermionic dark matter. There are still some operators not sensitive to the current dark matter direct and indirect search experiments. (C) 2012 Elsevier B.V. All rights reserved.
119245716
Constraining the interaction strength between dark matter and visible matter: I. Fermionic dark matter
In this work we study the constraints on the dark matter interaction with the standard model particles, from the observations of dark matter relic density, the direct detection experiments of CDMS and XENON, and the indirect detection of the (p) over bar /p ratio by PAMELA. A model independent way is adopted in the study by constructing the effective interaction operators between dark matter and standard model particles. The most general 4-fermion operators are investigated. We find that the constraints from different observations are complementary with each other. Especially the spin independent scattering gives very strong constraints for corresponding operators. In some cases the indirect detection of (p) over bar /p data can actually be more sensitive than the direct detection or relic density for light dark matter (less than or similar to 70 GeV). (C) 2011 Elsevier B.V. All rights reserved.
119275234
Electroweak radiative corrections to $W^+W^-\gamma$ production at the ILC
We provide and discuss the precision predictions for the $W^+W^-\gamma$ production at the ILC including the full electroweak (EW) one-loop corrections and high order initial state radiation (ISR) contributions in the Standard Model. The dependence of the leading order (LO) and EW corrected cross sections on the colliding energy is investigated. We find that the EW correction suppresses the LO cross section significantly, and the ISR effect beyond ${\cal O}(\alpha)$ is important near the threshold, but is negligible in the high energy region. We provide the LO and EW corrected distributions of the transverse momenta and rapidities of final $W^-$-boson and photon as well as the $W$-pair invariant mass. From the various kinematic distributions, we find that EW correction strongly depends on the final state phase space. We investigate the leptonic decays of the final W-boson pair by adopting the narrow width approximation (NWA), and find that the final produced photon and leptons can be well separated from each other.
119244329
QCD NLO and EW NLO corrections to $t\bar{t}H$ production with top quark decays at hadron collider
Higgs boson production associated with a top quark pair is an important process in studying the nature of the newly discovered Higgs boson at the LHC. In this letter, we report on our calculations including the next-to-leading order (NLO) QCD and NLO electroweak corrections to the pp → tt̄H process in the standard model. We present the integrated cross sections at the 14 TeV LHC and even at the future proton-proton colliders with √ s = 33 and 100 TeV. Our calculation includes the top quark subsequent decays by adopting the narrow width approximation. The kinematic distributions of Higgs boson and top quark decay products at the LHC are provided. We find that the O(α2sα2ew) corrections are quantitatively comparable with the O(α3sαew) corrections in some kinematic region.