Tests of Higgs Boson Couplings at a mu+mu- Collider

We investigate the potential of a muon collider for testing the presence of anomalous Higgs boson couplings. We consider the case of a light (less than $160 GeV$) Higgs boson and study the effects on the Higgs branching ratios and total width, which could be induced by the non standard couplings created by a class of dim=6 $SU(3)\times SU(2)\times U(1)$ gauge invariant operators satisfying the constraints imposed by the present and future hadronic and $e^-e^+$ colliders. For each operator we give the minimal value of the $\mu^+\mu^-$ integrated luminosity needed for the muon collider ($\mu C$) to improve these constraints. Depending on the operator and the Higgs mass, this minimal $\mu C$ luminosity lies between $0.1 fb^{-1}$ and $100 fb^{-1}$.Comment: 18 pages and 4 figures; version to be published in Phys. Rev.D. e-mail: [email protected]

Signals for Low Scale Gravity in the Process γγ→ZZ\gamma \gamma \to ZZ

We investigate the sensitivity of future photon-photon colliders to low scale gravity scenarios via the process $\gamma\gamma \to ZZ$ where the Kaluza-Klein boson exchange contributes only when the initial state photons have opposite helicity. We contrast this with the situation for the process $\gamma \gamma \to \gamma \gamma$ where the $t$ and $u$ channel also contribute. We include the one-loop Standard Model background whose interference with the graviton exchange determines the experimental reach in measuring any deviation from the Standard Model expectations and explore how polarization can be exploited to enhance the signal over background. We find that a 1 TeV linear collider has an experimental reach to mass scale of about 4 TeV in this channel.Comment: 20 pages, 8 figure

Signatures of the anomalous ZγZ\gamma and ZZ production at the lepton and hadron Colliders

The possible form of New Physics (NP) interactions affecting the ZZZ, $ZZ \gamma$ and $Z\gamma \gamma$ vertices, is critically examined. Their signatures and the possibilities to study them, through ZZ and $Z\gamma$ production, at the e^-e^+ Colliders LEP and LC and at the hadronic Colliders Tevatron and LHC, are investigated. Experimental limits obtained or expected on each coupling are collected. A simple theoretical model based on virtual effects due to some heavy fermions is used for acquiring some guidance on the plausible forms of these NP vertices. In such a case specific relations among the various neutral couplings are predicted, which can be experimentally tested and possibly used to constrain the form of the responsible NP structure.Comment: 17 pages and 9 figures, version to appear in Phys. ReV. e-mail: [email protected]

Implications for B→ηKB \to \eta K and B→Glueball+KB \to Glueball + K Modes from Observed Large B→η′K+XB\to \eta' K+X

The unexpectedly large branching ratios for $B\to \eta' K (\eta' X_s)$ decays could be of gluonic origin. We study the implications for $B\to \eta K (\eta X_s)$ and $P K (PX_s)$, where $P$ is the pseudoscalar glueball. In the mechanism proposed by Fritzsch, large branching ratios are predicted for these modes. The $B\to \eta K$ rate is barely within the experimental limit, and $B\to P K$, $PX_s$ could be at the 0.1% and 1% level, respectively. Smaller but less definite results are found for the mechanism of $g^* \to \eta' g$ via the gluon anomaly.Comment: 11 pages, revtex, no fig

Testing the Higgs boson gluonic couplings at LHC

We study Higgs + jet production at hadron colliders in order to look for new physics residual effects possibly described by the $dim=6$ operators {\O}_{GG} and {\widetilde\O}_{GG} which induce anomalous $Hgg$ and $Hggg$ couplings. Two ways for constraining these operators at LHC may be ~useful. The first is based on the total Higgs boson production rate induced by gluon-gluon fusion, in which the main cause of limitations are due to theoretical uncertainties leading to sensitivities of $|d_G|\simeq 3.\times 10^{-4}$ and $|\widetilde{d}_G|\simeq 1.4\times 10^{-3}$ for the corresponding anomalous couplings, in the mass range 100 GeV \lsim \mh \lsim 2~00 GeV. These results imply sensitivity to new physics scales of 51 and 24 TeV respectively. The second way investigated here concerns the shape of the Higgs transverse momentum; for which the theoretical uncertainties are less severe and the limitations are mainly induced by statistics. A simple analysis, based on the ratio of the number of events at large and low $p_T$ at LHC, leads to similar sensitivities, if only the $H\to \gamma \gamma$ decay mode is used. But the sensitivities can now be improved by a factor 2 to 10, depending on the Higgs mass, if the Higgs decay modes to $WW^*$, $ZZ^*$, $WW$, $ZZ$ are also used.Comment: 23 pages and 7 figures, version to appear in Phys.ReV.D. e-mail: [email protected]

Little Higgs model effects in γγ→γγ\gamma \gamma \to \gamma \gamma

Though the predictions of the Standard Model (SM) are in excellent agreement with experiments there are still several theoretical problems associated with the Higgs sector of the SM, where it is widely believed that some ``{\it new physics}'' will take over at the TeV scale. One beyond the SM theory which resolves these problems is the Little Higgs (LH) model. In this work we have investigated the effects of the LH model on \gggg scattering \cite{Choudhury:2006xa}.Comment: Talk given at LCWS06, Bangalore, 4 pages (style files included

How to reduce the negative impact of customer non-compliance: an empirical study

This article focuses on the notion of customer non-compliance with front-line employees' instructions and company's policies during the service encounter. The aim of the study is to offer an alternative solution to the issue of customer non-compliance, exploring the factors that reduce its negative impact on service quality. For that reason, we developed a conceptual framework integrating the negative influence of customer non-compliance on perceived service quality with three moderating effects. To test the validity of the framework, a hierarchical approach was followed and data were collected from 120 managers and 585 customers of 120 hotels. The results confirm the negative influence of customer non-compliance on perceived service quality and indicate three organizational factors as reducing moderators of this influence: customer orientation, service blueprinting effectiveness and employee empowerment. Based on these conclusions, important implications for academics and practitioners are drawn

Gauge boson couplings at LEP

A review is given of the measurements of triple and quartic couplings among the electroweak gauge bosons performed at LEP by the four experiments ALEPH, DELPHI, L3 and OPAL. Emphasis is placed on recently published results and on combinations of results performed by the LEP electroweak gauge-couplings group. All measurements presented are consistent with the Standard Model expectations.Comment: 6 pages, 7 figures. To be published in the proceedings of the BEACH04 conference, Chicago, June 27-July 3 200

Coherent pion production by neutrinos on nuclei

The main part of coherent pion production by neutrinos on nuclei is essentially determined by PCAC, provided that the leptonic momentum transferred square Q^2 remains sufficiently small. We give the formulas for the charged and neutral current cross sections, including also the small non-PCAC transverse current contributions and taking into account the effect of the \mu^- mass. Our results are compared with the experimental ones and other theoretical treatments.Comment: 18 pages, 4 figure

RacoonWW1.3: A Monte Carlo program for four-fermion production at e^+ e^- colliders

We present the Monte Carlo generator RacoonWW that computes cross sections to all processes e^+ e^- -> 4f and e^+ e^- -> 4f + gamma and calculates the complete O(alpha) electroweak radiative corrections to e^+ e^- -> W W -> 4f in the electroweak Standard Model in double-pole approximation. The calculation of the tree-level processes e^+ e^- -> 4f and e^+ e^- -> 4f + gamma is based on the full matrix elements for massless (polarized) fermions. When calculating radiative corrections to e^+ e^- -> W W -> 4f the complete virtual doubly-resonant electroweak corrections are included, i.e. the factorizable and non-factorizable virtual corrections in double-pole approximation, and the real corrections are based on the full matrix elements for e^+ e^- -> 4f + gamma. The matching of soft and collinear singularities between virtual and real corrections is done alternatively in two different ways, namely by using a subtraction method or by applying phase-space slicing. Higher-order initial-state photon radiation and naive QCD corrections are taken into account. RacoonWW also provides anomalous triple gauge-boson couplings for all processes e^+ e^- -> 4f and anomalous quartic gauge-boson couplings for all processes e^+ e^- -> 4f + gamma.Comment: 62 pages, LaTeX, elsart styl