119111473
Simulating graviton production at hadron colliders
Spin-2 particles and in particular gravitons are predicted in many new physics scenarios at the TeV scale. Depending on the details of models such new states might show up as a continuum, massless particles, or TeV scale resonances. Correspondingly, very different discovery signatures should be exploited, from the search of excesses in events with multi jets and large missing transverse energy, to resonances in weak boson or jet pair productions. We present a very general and flexible implementation in Mad-Graph/MadEvent of spin-2 particles interacting with the standard model particles via the energy momentum tensor, which encompasses all of the most popular TeV scale models featuring gravitons. By merging matrix elements with parton shower, we can generate inclusive samples of graviton + jets at the hadron colliders in several scenarios (ADD, zero-mass graviton and RS). We compare and validate our results against the corresponding next-to-leading order QCD calculations.
53994223
Next-to-leading order QCD predictions for A(0)Z(0) associated production at the CERN large hadron collider
We present the calculations of the complete next-to-leading order (NLO) QCD corrections (including supersymmetric QCD) to the inclusive total cross sections of the associated production processes pp -> A(0)Z(0)+X in the minimal supersymmetric standard model at the CERN Large Hadron Collider. Both the dimensional regularization scheme and the dimensional reduction scheme are used to organize the calculations, which yield the same NLO rates. The NLO correction can either enhance or reduce the total cross sections, but it generally efficiently reduces the dependence of the total cross sections on the renormalization/factorization scale. We also examine the uncertainty of the total cross sections due to the parton distribution function uncertainties.
119112269
Probing W+W−γ production and anomalous quartic gauge boson couplings at the CERN LHC
A bstractTriple gauge boson associated production at the LHC serves as an interesting channel to test the robustness of the Standard Model. Any deviation from its SM prediction may indicate possible existence of relevant new physics, e.g., anomalous quartic gauge boson couplings. In this paper, a Monte-Carlo feasibility study of measuring W+W−γ production with pure leptonic decays and probing anomalous quartic gauge-boson (e.g., WWγγ) couplings, is presented in detail for the first time, with parton shower and detector simulation effects taken into account. Our results show that at the $ \sqrt{s}=14 $ TeV LHC with an integrated luminosity of 100 (30) fb−1, one can reach a significance of 9 (5) σ to observe the SM W+W−γ production, and can constrain at the 95% C.L. the anomalous WWγγ coupling parameters, e.g., $ a{{{_{0,c}^W}} \left/ {{{\varLambda^2}}} \right.} $ (see ref. [16] for their definitions), at 1 × 10−5 GeV−2 level, respectively.
10401834
Effects of R-parity violation in unpolarized top quark decay into a polarized W boson
We calculate one-loop R-parity violating corrections to the top quark decay into a bottom quark and a polarized W-gauge boson. The corrections are presented according to the total corrections, the longitudinal corrections and the transverse corrections, respectively. We compared our results with the O({alpha}{sub s}) QCD corrections, the O({alpha}) electroweak (EW) and finite width corrections, and also the supersymmetric (SUSY) corrections with R-parity conservation, respectively.
18038456
Supersymmetric electroweak corrections to heavier top squark decay into a lighter top squark and neutral Higgs boson
We calculate the Yukawa corrections of order ${\cal O}(\alpha_{ew}m_{t(b)}^2/m_W^2)$, ${\cal O}(\alpha_{ew}m_{t(b)}^3/m_W^3)$ and ${\cal O}(\alpha_{ew}m_{t(b)}^4/m_W^4)$ to the widths of the decays $\tilde t_2\to \tilde t_1 + (h^0,H^0,A^0)$ in the Minimal Supersymmetric Standard Model, and perform a detailed numerical analysis. We also compare the results with the ones presented in an earlier literature, where the ${\cal O}(\alpha_{s})$ SUSY-QCD corrections to the same three decay processes have been calculated. 
Our numerical results show that for the decays $\tilde t_2\to \tilde t_1 + h^{0}$, $\tilde t_2\to \tilde t_1 + H^{0}$, the Yukawa corrections are significant in most of the parameter range, which can reach a few ten percent, and for the decay $\tilde t_2\to\tilde t_1 + A^{0}$, the Yukawa corrections are relatively smaller, which are only a few percent. The numerical calculations also show that using the running quark masses and the running trilinear coupling $A_t$, which include the QCD, SUSY-QCD, SUSY-Electroweak effects and resume all high order ($\tan\beta$)-enhanced effects, can vastly improve the convergence of the perturbation expansion. We also discuss the effects of the running of the higgsino mass parameter $\mu$ on the corrections, and find that they are significant, too, especially for large $\tan\beta$.
53064083
Next-to-leading order QCD predictions for pair production of neutral Higgs bosons at the CERN Large Hadron Collider
We present the calculations of the complete next-to-leading-order (NLO) inclusive total cross sections for pair production of neutral Higgs bosons through b (b) over bar annihilation in the minimal supersymmetric standard model at the CERN Large Hadron Collider. In our calculations, we used both the dimensional regularization scheme and the dimensional reduction scheme and found that the NLO total cross sections in these two schemes are the same. Our results show that the b (b) over bar -annihilation contributions can exceed those of gg fusion and q (q) over bar annihilation for h(0)H(0), A(0)h(0), and A(0)H(0) productions when tan beta is large. In the case of mu > 0, the NLO corrections enhance the leading-order total cross sections significantly, reaching a few tens of percent, while for mu < 0, the corrections are relatively small, and are negative in most of parameter space. Moreover, the NLO QCD corrections reduce the dependence of the total cross sections on the renormalization/factorization scale, especially for mu < 0. We also used the CTEQ6.1 parton distribution function sets to estimate the uncertainty of leading-order and NLO total cross sections, and found that the uncertainty arising from the choice of parton distribution functions increases with the increasing m(A)(0).
120176772
Design of the local trigger board for the Daya Bay reactor neutrino experiment
We have designed a local trigger board for the Daya Bay reactor neutrino experiment, which is aimed to measure the neutrino mixing angle sin(2) 2 theta(13) with a precision down to 1% level. The local trigger board processes both the total number of coincident photomultiplier tube (PMT) hits and the PMT energy sum to make trigger decisions. With this design, a high trigger probability is achieved to meet the system requirement. The design of the local trigger board is presented. (C) 2011 Elsevier B.V. All rights reserved.
15826730
Higgs Searches at the Tevatron
One of the highest priority physics goals for the upgraded Tevatron experiments, CDF and D0, is the search for the Higgs boson. We present the initial results from both experiments, based on 40--90 pb$^{-1}$ integrated luminosity, of Higgs searches in several final states, including $WH$ and $ZH$, $H\to WW$, and doubly-charged Higgs.