119222436
Single production of the doubly charged Higgs boson via e\gamma collision in the Higgs triplet model
The Higgs triplet model (HTM) predicts the existence of a pair of doubly charged Higgs bosons $H^{\pm \pm}$. Single production of $H^{\pm \pm}$ via e collision at the next generation e+e- International Linear Collider (ILC) and the Large Hadron electron Collider (LHeC) is considered. The numerical results show that the production cross sections are very sensitive to the neutrino oscillation parameters. Their values for the inverted hierarchy mass spectrum are larger than those for the normal hierarchy mass spectrum at these two kinds of collider experiments. With reasonable values of the relevant free parameters, the possible signals of the doubly charged Higgs bosons predicted by the HTM might be detected in future ILC experiments.
119266191
The anomalous top quark coupling tqg and tW production at the LHC
Abstract Many new physics models beyond the standard model ( SM ) can give rise to the large anomalous top couplings tqg ( q = u and c ). We focus our attention on these couplings induced by the topcolor-assisted technicolor ( TC 2 ) model and the littlest Higgs model with T -parity (called LHT model), and consider their contributions to the production cross section and the charge asymmetry for tW production at the LHC . We find that the anomalous top coupling tqg induced by these two kinds of new physics models can indeed generate sizable charge asymmetry. The correction effects of the LHT model on the production cross sections of the processes p p → t W − + X and p p → t ¯ W + + X are significant large, which might be detected at the LHC .
125128095
Search for tau --> mu gamma decay at Belle
11914733
Search for invisible decays of Higgs bosons in the vector boson fusion and associated ZH production modes
A search for invisible decays of Higgs bosons is performed using the vector boson fusion and associated ZH production modes. In the ZH mode, the Z boson is required to decay to a pair of charged leptons or a $$\mathrm {b}\overline{\mathrm {b}}$$bb¯ quark pair. The searches use the 8┬á$$\text {TeV}$$TeV pp collision dataset collected by the CMS detector at the LHC, corresponding to an integrated luminosity of up to 19.7┬á$$\text {fb}^{-1}$$fb-1. Certain channels include data from 7┬á$$\text {TeV}$$TeV collisions corresponding to an integrated luminosity of 4.9┬á$$\text {fb}^{-1}$$fb-1. The searches are sensitive to non-standard-model invisible decays of the recently observed Higgs boson, as well as additional Higgs bosons with similar production modes and large invisible branching fractions. In all channels, the observed data are consistent with the expected standard model backgrounds. Limits are set on the production cross section times invisible branching fraction, as a function of the Higgs boson mass, for the vector boson fusion and ZH production modes. By combining all channels, and assuming standard model Higgs boson cross sections and acceptances, the observed (expected) upper limit on the invisible branching fraction at $$m_\mathrm {H}=125$$mH=125┬á$$\text {GeV}$$GeV is found to be 0.58┬á(0.44) at 95┬á% confidence level. We interpret this limit in terms of a Higgs-portal model of dark matter interactions.
109931424
Measurements of Higgs boson production and couplings in diboson final states with the ATLAS detector at the LHC
Measurements are presented of production properties and couplings of the recently discovered Higgs boson using the decays into boson pairs, H --> gamma-gamma, H --> ZZ* --> 4 leptons and H --> WW --> 2 leptons + 2 neutrinos. The results are based on the complete pp collision data sample recorded by the ATLAS experiment at the CERN Large Hadron Collider at centre-of-mass energies of 7 TeV and 8 TeV, corresponding to an integrated luminosity of about 25/fb. Evidence for Higgs boson production through vector-boson fusion is reported. Results of combined fits probing Higgs boson couplings to fermions and bosons, as well as anomalous contributions to loop-induced production and decay modes, are presented. All measurements are consistent with expectations for the Standard Model Higgs boson.
55688676
THE RF DESIGN OF AN HOM POLARIZED RF GUN FOR THE ILC
The ILC requires a polarized electron beam. While a highly polarized beam can be produced by a GaAs-type cathode in a DC gun of the type currently in use at SLAC, JLAB and elsewhere, the ILC injector system can be simplified and made more efficient if a GaAs-type cathode can be combined with a low emittance RF gun. Since this type of cathode is known to be extremely sensitive to vacuum contamination including back bombardment by electrons and ions, any successful polarized RF gun must have a significantly improved operating vacuum compared to existing RF guns. We present a new RF design for an L-Band normal conducting (NC) RF gun for the ILC polarized electron source. This design incorporates a higher order mode (HOM) structure, whose chief virtue in this application is an improved conductance for vacuum pumping on the cathode. Computer simulation models have been used to optimize the RF parameters with two principal goals: first to minimize the required RF power; second to reduce the peak surface field relative to the field at the cathode in order to suppress field emitted electron bombardment. The beam properties have been simulated initially using PARMELA. Vacuum and other practical issues for implementing this design are discussed.
18863277
Measurement of the muonic branching fractions of the narrow upsilon resonances.
The decay branching fractions of the three narrow Upsilon resonances to mu(+)mu(-) have been measured by analyzing about 4.3 fb(-1) e(+)e(-) data collected with the CLEO III detector. The branching fraction B(Upsilon(1S)-->mu(+)mu(-))=(2.49+/-0.02+/-0.07)% is consistent with the current world average, but B(Upsilon(2S)-->mu(+)mu(-))=(2.03+/-0.03+/-0.08)% and B(Upsilon(3S)-->mu(+)mu(-))=(2.39+/-0.07+/-0.10)% are significantly larger than prior results. These new muonic branching fractions imply a narrower total decay width for the Upsilon(2S) and Upsilon(3S) resonances and lower other branching fractions that rely on these decays in their determination.