119217158
Factorization and resummation for single color-octet scalar production at the LHC
Heavy colored scalar particles appear in a variety of new physics (NP) models and could be produced at the Large Hadron Collider. Knowing the total production cross section is important for searching for these states and establishing bounds on their masses and couplings. Using soft-collinear effective theory, we derive a factorization theorem for the process $pp\ensuremath{\rightarrow}SX$, where $S$ is a color-octet scalar, that is applicable to any NP model provided the dominant production mechanism is gluon-gluon fusion. The factorized result for the inclusive cross section is similar to that for the standard model Higgs production; however, differences arise due to color exchange between initial and final states. We provide formulas for the total cross section with large (partonic) threshold logarithms resummed to next-to-leading logarithm accuracy. The resulting $K$ factors are similar to those found in Higgs production. We apply our formalism to the Manohar-Wise model and find that the next-to-leading logarithm cross section is roughly 2 times (3 times) as large as the leading order cross section for a color-octet scalar of mass of 500 GeV (3 TeV). A similar enhancement should appear in any NP model with color-octet scalars.
8812146
Rare radiative exclusive B decays in soft-collinear effective theory
We consider rare radiative B decays such as $\overline{B}\ensuremath{\rightarrow}{K}^{*}\ensuremath{\gamma}$ or $\overline{B}\ensuremath{\rightarrow}\ensuremath{\rho}\ensuremath{\gamma}$ in soft-collinear effective theory (SCET) and show that the decay amplitudes are factorized to all orders in ${\ensuremath{\alpha}}_{s}$ and at leading order in ${\ensuremath{\Lambda}}_{\mathrm{QCD}}{/m}_{b}.$ By employing two-step matching, we classify the operators for radiative B decays in powers of a small parameter $\ensuremath{\lambda}(\ensuremath{\sim}\sqrt{{\ensuremath{\Lambda}}_{\mathrm{QCD}}{/m}_{b}})$ and obtain the relevant operators to order $\ensuremath{\lambda}$ in ${\mathrm{SCET}}_{\mathrm{I}}.$ These operators are constructed with or without spectator quarks including the four-quark operators contributing to annihilation and W-exchange channels. And we employ ${\mathrm{SCET}}_{\mathrm{II}}$ where the small parameter becomes of order ${\ensuremath{\Lambda}}_{\mathrm{QCD}}{/m}_{b},$ and evolve the operators in order to compute the decay amplitudes for rare radiative decays in soft-collinear effective theory. We show explicitly that the contributions from the annihilation channels and the W-exchange channels vanish at leading order in SCET. We present the factorized result for the decay amplitudes in rare radiative B decays at leading order in SCET and at next-to-leading order in ${\ensuremath{\alpha}}_{s}.$
118681007
Endpoint behavior of high-energy scattering cross sections
In high-energy processes near the endpoint, there emerge new contributions associated with spectator interactions. Away from the endpoint region, these new contributions are suppressed compared to the leading contribution, but the leading contribution becomes suppressed as we approach the endpoint and the new contributions become comparable. We present how the new contributions scale as we reach the endpoint and show that they are comparable to the suppressed leading contributions in deep inelastic scattering by employing a power-counting analysis. The hadronic tensor in deep inelastic scattering is shown to factorize including the spectator interactions, and it can be expressed in terms of the light cone distribution amplitudes of initial hadrons. We also consider the contribution of the spectator contributions in Drell-Yan processes. Here the spectator interactions are suppressed compared to double parton annihilation according to the power counting.
118701906
Nonperturbative charming penguin contributions to isospin asymmetries in radiative B decays
Recent experimental data on the radiative decays B{yields}V{gamma}, where V is a light vector meson, find small isospin violation in B{yields}K*{gamma} while isospin asymmetries in B{yields}{rho}{gamma} are of order 20%, with large uncertainties. Using soft-collinear effective theory, we calculate isospin asymmetries in these radiative B decays up to O(1/m{sub b}), also including O(v{alpha}{sub s}) contributions from nonperturbative charming penguins (NPCP). In the absence of NPCP contributions, the theoretical predictions for the asymmetries are a few percent or less. Including the NPCP can significantly increase the isospin asymmetries for both B{yields}V{gamma} modes. We also consider the effect of the NPCP on the branching ratio and CP asymmetries in B{sup {+-}}{yields}V{sup {+-}}{gamma}.
53724420
Soft Wilson lines in the soft-collinear effective theory
The effects of the soft gluon emission in hard scattering processes at the phase boundary are resummed in the soft-collinear effective theory (SCET). In SCET, the soft gluon emission is decoupled from the energetic collinear part, and is obtained by the vacuum expectation value of the soft Wilson-line operator. The form of the soft Wilson lines is universal in deep inelastic scattering, in the Drell-Yan process, in the jet production from e{sup +}e{sup -} collisions, and in the {gamma}*{gamma}*{yields}{pi}{sup 0} process, but its analytic structure is slightly different in each process. The anomalous dimensions of the soft Wilson-line operators for these processes are computed along the lightlike path at leading order in SCET and to first order in {alpha}{sub s}, and the renormalization group behavior of the soft Wilson lines is discussed.
17641368
Factorization and resummation for color octet production
We discuss the production of heavy colored paricles at the Large Hadron Collider (LHC) through gluon-gluon fusion process. A factorization theorem is obtained for this process using Soft Collinear Effective Theory. Our factorization theorem does not depend on any assumptions regarding the physics above the mass of the heavy colored particle. In this sense it is universal. The matching coefficient at the heavy particle mass scale depends however on the unkown physics above that scale and thus it is model dependent. 
Due to the large mass of the heavy colored particle, i.e., the hard scale and near the partonic kinematic threshold for production of such particles a resummation of large logarithms needs to be performed. The resummation is justified due to the dominance of the gluon distribution function at small $x$. For phenomenological purposes we utilize the Manohar-Wise model.
109775896
Results of radiation test of the cathode front-end board for CMS endcap muon chambers
Abstract After a brief overview of the CMS EMU electronics system, results on radiation induced single event effects, total ionization dose and displacement effects will be reported. These results are obtained by irradiating the components on electronics boards with 63 MeV protons and 1 MeV neutrons. During the proton irradiation, the electronics board was fully under power, all components on the board were active and the data were read out in the same way as designed for CMS. No deterioration of analog performance for each of the three CMOS ASICs on the tested board was observed, up to a dose of 10 krad . Each of the tested FPGAs survived beyond the dose of 30 krad . No single event latch-up was detected for the CMOS ASICs up to a proton fluence of 2×10 12 cm −2 . Single Event Upsets (SEU) in FPGAs were detected and their cross-sections measured. SEU mitigation with triple module redundancy and voting was implemented and tested.