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).
119302515
Higgs Boson Production via Gluon Fusion in the Standard Model with four Generations
Higgs bosons can be produced copiously at the LHC via gluon fusion induced by top and bottom quark loops, and can be enhanced strongly if extra heavy quarks exist. We present results for Higgs+zero-, one- and two-jet production at the LHC operating at 7 and 14 TeV collision energy, in both the standard model and the 4th generation model, by evaluating the corresponding heavy quark triangle, box, and pentagon Feynman diagrams. We compare the results by using the effective Higgs-gluon interactions in the limit of heavy quarks with the cross sections including the full mass dependences. NLO effects on Higgs+zero-jet production rate with full mass dependence are presented for the first time consistently in the 4th generation model. Our results improve the theoretical basis for fourth generation effects on the Higgs boson search at the LHC.
13008347
ZZ jet and Graviton jet at NLO QCD: recent applications using GOLEM methods
In this talk we discuss recent progress concerning precise predictions for hadron colliders. We show results of two applications of tensor reduction using GOLEM methods: the next-to-leading order (NLO) corrections to pp {yields} ZZ + jet as an important background for Higgs particle and new physics searches at hadron colliders, and the NLO corrections to graviton plus jet hadroproduction, which is an important channel for graviton searches at the Tevatron and the LHC.
119183590
Photon-pair jet production via gluon fusion at the LHC
Photon-pair direct or jet-associated production is important for relevant standard model measurement, Higgs and new physics searches at the Large Hadron Collider (LHC). The loop-induced gluon-fusion process gg -> gamma gamma g, which formally contributes only at the next-to-next-to-leading order to gamma gamma j productions, may get enhanced by the large gluon flux at the LHC. We have checked and confirmed previous results on gg -> gamma gamma (Dicus and Willenbrock 1988 Phys. Rev. D37 1801), gamma gamma g (de Florian andKunszt 1999 Phys. Lett. B 460 184) at one loop, using the traditional Feynman diagram based approach, taking into account the quark mass effects, and updated them further for the 7 and 14 TeV LHC with new inputs and settings. We provide the details and results of the calculations, which involve manipulation of rank-5 pentagon integrals. Our results show that the gluon-fusion process can contribute about 10% of the Born result, especially at small M-gamma gamma and P-gamma gamma(T), and increase further the overall scale uncertainty. Top quark loop effects are examined in detail, which become important near or above the threshold M-gamma gamma greater than or similar to 2m(t).
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.
53532246
Associated production of neutral Higgs boson with squark pair in the minimal supersymmetric standard model with explicit CP violation at the CERN LHC
We investigate the associated production of neutral Higgs boson with squark pair in the minimal supersymmetric standard model with and without explicit $CP$ violation, respectively. We show that the dominant productions in both cases are always ones of the lightest neutral Higgs boson associated with the lightest stop pair, which can reach a few pb, in the ranges of parameters allowed by constraints from the electric dipole moment experiments. In most of the parameter space, the total cross sections in the case with explicit $CP$ violation are significantly enhanced, compared with ones without explicit $CP$ violation. For some special parameters, several orders of magnitude enhancement can be obtained.
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.
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.