Electroweak and QCD corrections to Higgs-boson production in vector-boson fusion at the LHC

Radiative corrections of strong and electroweak interactions are presented at next-to-leading order for Higgs-boson production in the weak-boson-fusion channel at the LHC. The calculation includes all weak-boson fusion and quark-antiquark annihilation diagrams as well as all related interferences. The electroweak corrections, which also include real corrections from incoming photons and leading heavy-Higgs-boson effects at two-loop order, are of the same size as the QCD corrections, viz. typically at the level of 5-10% for a Higgs-boson mass up to \sim 700 GeV. In general, they do not simply rescale differential distributions, but induce distortions at the level of 10%. The discussed corrections have been implemented in a flexible Monte Carlo event generator.Comment: 6 pages, LaTeX, 4 postscript figures, to appear in the proceedings of the "8th International Symposium on Radiative Corrections (RADCOR07)", Florence, Italy, October 1-5, 200

Precision Calculations for Associated WH and ZH Production at Hadron Colliders

Recently the next-to-next-to-leading order QCD corrections and the electroweak O(alpha) corrections to the Higgs-strahlung processes ppbar/pp -> WH/ZH + X have been calculated. Both types of corrections are of the order of 5-10%. In this article the various corrections are briefly discussed and combined into state-of-the-art predictions for the cross sections. The theoretical uncertainties from renormalization/factorization scales and from the parton distribution functions are discussed.Comment: 8 pages, Contributed to 3rd Les Houches Workshop: Physics at TeV Collider

Local and global spontaneous calcium events regulate neurite outgrowth and onset of GABAergic phenotype during neural precursor differentiation

Neural stem cells can generate in vitro progenitors of the three main cell lineages found in the CNS. The signaling pathways underlying the acquisition of differentiated phenotypes in these cells are poorly understood. Here we tested the hypothesis that Ca2+ signaling controls differentiation of neural precursors. We found low-frequency global and local Ca2+ transients occurring predominantly during early stages of differentiation. Spontaneous Ca2+ signals in individual precursors were not synchronized with Ca2+ transients in surrounding cells. Experimentally induced changes in the frequency of local Ca2+signals and global Ca2+ rises correlated positively with neurite outgrowth and the onset of GABAergic neurotransmitter phenotype, respectively. NMDA receptor activity was critical for alterations in neuronal morphology but not for the timing of the acquisition of the neurotransmitter phenotype. Thus, spontaneous Ca2+ signals are an intrinsic property of differentiating neurosphere-derived precursors. Their frequency may specify neuronal morphology and acquisition of neurotransmitter phenotype

Non local parity transformations and anomalies

We present an alternative derivation of the parity anomaly for a massless Dirac field in 2+1 dimensions coupled to a gauge field. The anomaly functional, a Chern-Simons action for the gauge field, is obtained from the non-trivial Jacobian corresponding to a non local symmetry of the Pauli-Villars regularized action. That Jacobian is well-defined, finite, and yields the standard Chern-Simons term when the cutoff tends to infinity.Comment: 10 pages, Latex fil

CPsuperH2.3: an Updated Tool for Phenomenology in the MSSM with Explicit CP Violation

We describe the Fortran code CPsuperH2.3, which incorporates the following updates compared with its predecessor CPsuperH2.0. It implements improved calculations of the Higgs-boson masses and mixing including stau contributions and finite threshold effects on the tau-lepton Yukawa coupling. It incorporates the LEP limits on the processes e^+ e^- to H_i Z, H_i H_j and the CMS limits on H_i to tau^+ tau^- obtained from 4.6/fb of data at a centre-of-mass energy of 7 TeV. It also includes the decay mode H_i to Z gamma and the Schiff-moment contributions to the electric dipole moments of Mercury and Radium225, with several calculational options for the case of Mercury. These additions make CPsuperH2.3 a suitable tool for analyzing possible CP-violating effects in the MSSM in the era of the LHC and a new generation of EDM experimentsComment: 31 pages, 10 eps figures, 7 tables; H to Z gamma and SM BRs included; To appear in CPC; Typos in Eq.(A.2) corrected;The program may be obtained from http://www.hep.man.ac.uk/u/jslee/CPsuperH.html, or by contacting the first author at [email protected]; A comment added after Eq.(15) and a typo in Eq.(A.4) correcte

Electroweak and QCD corrections to Higgs production via vector-boson fusion at the LHC

The radiative corrections of the strong and electroweak interactions are calculated at next-to-leading order for Higgs-boson production in the weak-boson-fusion channel at hadron colliders. Specifically, the calculation includes all weak-boson fusion and quark--antiquark annihilation diagrams to Higgs-boson production in association with two hard jets, including all corresponding interferences. The results on the QCD corrections confirm that previously made approximations of neglecting s-channel diagrams and interferences are well suited for predictions of Higgs production with dedicated vector-boson fusion cuts at the LHC. The electroweak corrections, which also include real corrections from incoming photons and leading heavy-Higgs-boson effects at two-loop order, are of the same size as the QCD corrections, viz. typically at the level of 5-10% for a Higgs-boson mass up to \sim 700 GeV. In general, both types of corrections do not simply rescale differential distributions, but induce distortions at the level of 10%. The discussed corrections have been implemented in a flexible Monte Carlo event generator.Comment: 33 pages, LaTeX, 24 postscript figure

Electroweak corrections to Higgs-strahlung off W/Z bosons at the Tevatron and the LHC with HAWK

The associate production of Higgs bosons with W or Z bosons, known as Higgs-strahlung, is an important search channel for Higgs bosons at the hadron colliders Tevatron and LHC for low Higgs-boson masses. We refine a previous calculation of next-to-leading-order electroweak corrections (and recalculate the QCD corrections) upon including the leptonic decay of the W/Z bosons, thereby keeping the fully differential information of the 2-lepton + Higgs final state. The gauge invariance of the W/Z-resonance treatment is ensured by the use of the complex-mass scheme. The electroweak corrections, which are at the level of -(5-10)% for total cross sections, further increase in size with increasing transverse momenta p_T in differential cross sections. For instance, for p_T,H >~ 200GeV, which is the interesting range at the LHC, the electroweak corrections to WH production reach about -14% for M_H = 120GeV. The described corrections are implemented in the HAWK Monte Carlo program, which was initially designed for the vector-boson-fusion channel, and are discussed for various distributions in the production channels pp / p \bar p -> H + l nu_l / l^-l^+ / nu_l \bar nu_l + X.Comment: 22 p

Towards LHC phenomenology at the loop level: A new method for one-loop amplitudes

A precise understanding of LHC phenomenology requires the inclusion of one-loop corrections for multi-particle final states. In this talk we describe a semi-numerical method to compute one-loop amplitudes with many external particles and present first applications.Comment: 5 pages latex, 1 ps fig., 1 eps fig., Conference Proceedings Radcor 200