"The European Physical Journal C"

Yang, T.;Andreopoulos, C.;Gallagher, H.;Hofmann, K.;Kehayias, P.

doi: 10.1140/epjc/s10052-009-1094-zpmid: N/A

Abstract We present a detailed description of a new hadronic multiparticle production model for use in neutrino interaction simulations. Its validity spans a wide invariant mass range starting from the pion production threshold. This model focuses on the low invariant mass region which is probed in few-GeV neutrino interactions and is of particular importance to neutrino oscillation experiments using accelerator and atmospheric fluxes. It exhibits reasonable agreement with a wide variety of experimental data. We also describe measurements that can be made in upcoming experiments that can improve modeling in areas where uncertainties are currently large.

Kanemura, Shinya;Tsumura, Koji

doi: 10.1140/epjc/s10052-009-1077-0pmid: N/A

Abstract We study the impact of dimension-six operators on single- and double-Higgs production rates via gluon fusion at the Large Hadron Collider (LHC). If the top-Yukawa coupling is modified by some new physics whose scale is of the TeV scale, its effect changes the cross sections of single-Higgs production gg→H and double-Higgs production gg→HH through the top-loop diagram. In particular, double-Higgs production can receive significant enhancement from the effective top-Yukawa coupling and the new dimension-five coupling \(t{\bar{t}}HH\) which are induced by the dimension-six operator. Comparing these results to the forthcoming data at the LHC, one can extract information of the dimension-six operators relevant to the top quark and the Higgs boson.

Kersting, N.

doi: 10.1140/epjc/s10052-009-1063-6pmid: N/A

Abstract In Split-Supersymmetry models, where the only non-Standard Model states produceable at LHC-energies consist of a gluino plus neutralinos and charginos, it is conventionally accepted that only mass differences among these latter are measurable at the LHC. The present work shows that application of a simple ‘Kinematic Selection’ technique allows for full reconstruction of neutralino and chargino masses from one event, in principle. A Monte Carlo simulation demonstrates the feasibility of using this technique at the LHC.

Fayette, F.;Krasny, M. W.;Płaczek, W.;Siódmok, A.

doi: 10.1140/epjc/s10052-009-1084-1pmid: N/A

Abstract This paper is the second of the series of papers proposing dedicated strategies for precision measurements of the Standard Model parameters at the LHC. The common feature of these strategies is their robustness with respect to the systematic measurement and modeling error sources. Their impact on the precision of the measured parameters is reduced using dedicated observables and dedicated measurement procedures which exploit flexibilities of the collider and detector running modes. In the present paper we focus our attention on the measurement of the charge asymmetry of the W-boson mass. This measurement is of primordial importance for the LHC experimental program, both as a direct test of the charge-sign-independent coupling of the W-bosons to the matter particles and as a necessary first step towards the precision measurement of the charge-averaged W-boson mass. We propose and evaluate the LHC-specific strategy to measure the mass difference between the positively and negatively charged W-bosons, \(M_{W^{+}}-M_{W^{-}}\) . We show that its present precision can be improved at the LHC by a factor of 20. We argue that such a precision is beyond the reach of the standard measurement and calibration methods imported to the LHC from the Tevatron program.

Martin, A. D.;Nockles, C.;Ryskin, M. G.;Shuvaev, A. G.;Teubner, T.

doi: 10.1140/epjc/s10052-009-1087-ypmid: N/A

Abstract We justify the practical use of the Shuvaev integral transform approach to calculate the skewed distributions, needed to describe diffractive processes, directly from the conventional diagonal global parton distributions. We address doubts which have been raised about this procedure. We emphasise that the approach, on the one hand, satisfies all theoretical requirements, and, on the other hand, is consistent with DVCS data at NLO. We construct an easily accessible package for the computation of these skewed distributions.

Godbole, R. M.;Grau, A.;Pancheri, G.;Srivastava, Y. N.

doi: 10.1140/epjc/s10052-009-1093-0pmid: N/A

Abstract In this paper we apply to the photoproduction total cross section a model we have proposed for purely hadronic processes and which is based on QCD mini-jets and soft gluon re-summation. We compare the predictions of our model with the HERA data as well as with other models. For cosmic rays, our model predicts substantially higher cross sections at TeV energies than models based on factorization, but lower than models based on mini-jets alone, without soft gluons. We discuss the origin of this difference.

Veliev, Elşen Veli;Kaya, Gülşah

doi: 10.1140/epjc/s10052-009-1080-5pmid: N/A

Abstract In the present work, D s and B s meson parameters are investigated in the framework of thermal QCD sum rules. The temperature dependences of the mass and the leptonic decay constants are investigated by using Borel transform sum rules and Hilbert moment sum rules. To increase the sensitivity, the vacuum contributions are subtracted from the thermal expressions and the temperature dependences of the leptonic decay constants and meson masses are studied.

Liu, Bochao;Büscher, Markus;Guo, Feng-Kun;Hanhart, Christoph;Meißner, Ulf-G.

doi: 10.1140/epjc/s10052-009-1083-2pmid: N/A

Abstract We investigate the interplay between crossed channel final state interactions and the constraints from two-particle unitarity for the reactions J/ψ→V π π and \(VK\bar{K}\) , where V is either ω or φ. Using a model where the parameters are largely constrained by other sources, we find that, although small, crossed channel final state interaction can influence the amplitudes considerably, in special areas of phase space. These results cast doubt on the inapplicability of unitarity constraints on production amplitudes as recently claimed in the literature.

Mok, A. W. K.;Sebastian, K. J.

doi: 10.1140/epjc/s10052-009-1091-2pmid: N/A

Abstract Using the helicity formalism, we calculate the combined angular distribution function of the two gamma photons and the electron in the cascade process \({\bar{p}p}\to{}^{3}{D}_{2}\to\chi_{J}+\gamma_{1}\to(\psi +\gamma_{2})+\gamma_{1}\to({e}^{+}+{e}^{-})+\gamma_{1}+\gamma_{2}\) (J=0,1,2), when \({\bar{p}}\) and p are arbitrarily polarized. We also present the partially integrated angular distribution functions in six different cases. Our results show that by measuring the two-particle angular distribution of γ 1 and γ 2 and that of γ 1 and e −, one can determine the relative magnitudes as well as the relative phases of all the helicity amplitudes in the two radiative decay processes 3 D 2→χ J +γ 1 and χ J →ψ+γ 2.

Wang, Zhi-Gang

doi: 10.1140/epjc/s10052-009-1097-9pmid: N/A

Abstract In this article, we assume that there exists a scalar \(D_{s}^{\ast}{\bar{D}}_{s}^{\ast}\) molecular state in the J/ψ φ invariant mass distribution, and we study its mass using the QCD sum rules. The predictions depend heavily on the two criteria (pole dominance and convergence of the operator product expansion) of the QCD sum rules. The value of the mass is about \(M_{D_{s}^{\ast}{\bar{D}}_{s}^{\ast}}=(4.43\pm0.16)\) GeV, which is inconsistent with the experimental data. The \(D_{s}^{\ast}{\bar{D}}_{s}^{\ast}\) is probably a virtual state and is not related to the meson Y(4140). Another possibility, such as a hybrid charmonium, is not excluded.