Search results for "waves"
showing 10 items of 1766 documents
Tau polarization at the Z peak from the acollinearity between both τ-decay products
1992
21 páginas, 4 figuras, 6 tablas.
Tau weak dipole moments from azumthal asymmetries
1999
We show that transverse and normal single-$tau$ polarization of $tau$ pairs produced at $e^+$ $e^-$ unpolarized collisions, at the $Z$ peak, are sensitive to weak (magnetic and electric) dipole moments of the $tau$. We also show how these components of the $\tau$ polarization are accessible by measuring appropriate azimuthal asymmetries in the angular distribution of its decay products. Sensitivities of the order of $10^{-18}$ $e\cdot cm$, for the weak-electric dipole moment, and $10^{-4}$ ($10^{-3}$), for the real (imaginary) part of the weak-magnetic dipole moment of $\tau$, may be achieved. Compatible bounds are also presented from spin-spin correlated asymmetries.
Finite volume treatment of ππ scattering and limits to phase shifts extraction from lattice QCD
2012
We study theoretically the effects of finite volume for pipi scattering in order to extract physical observables for infinite volume from lattice QCD. We compare three different approaches for pipi scattering (lowest order Bethe-Salpeter approach, N/D and inverse amplitude methods) with the aim to study the effects of the finite size of the box in the potential of the different theories, specially the left-hand cut contribution through loops in the crossed t,u-channels. We quantify the error made by neglecting these effects in usual extractions of physical observables from lattice QCD spectra. We conclude that for pipi phase-shifts in the scalar-isoscalar channel up to 800 MeV this effect i…
Final State Interactions in Kaon Decays
2001
27 páginas, 1 figura, 2 tablas.-- PACS: 13.25.Es; 11.30.Er; 13.85.Fb; 11.55.Fv.-- arXiv:hep-ph/0007208v1
Discovering and Studying Bileptons with e-e- Collisions
1997
We analyze the prospects for discovering and unraveling the nature of doubly-charged bileptons at a linear collider of the next generation running in its electron-electron colliding mode. We stress the importance of initial state radiation, beam spread and polarization, and compute the discovery bounds. The gauge nature of vector bileptons can be determined by studying hard photon emission.
Probing the neutrino mass hierarchy with Super-Kamiokande
2012
We show that for recently discovered large values of theta(13), a superbeam with an average neutrino energy of ~ 5 GeV, such as those being proposed at CERN, if pointing to Super-Kamiokande (L = 8770 km), could reveal the neutrino mass hierarchy at 5 sigma in less than two years irrespective of the true hierarchy and CP phase. The measurement relies on the near resonant matter effect in the numu to nue oscillation channel, and can be done counting the total number of appearance events with just a neutrino beam.
The COMPASS experiment at CERN
1998
Abstract The recently approved COMPASS experiment attempts a measurement of the gluon polarization around η ⋍ 0.1 with a precision of δ(Δ g / g ) ⋍ 0.1. The experiment uses open charm muo-production and large PT hadron pairs to tag the photon-gluon fusion process. COMPASS will also cover a rich spin-physics program in polarized DIS.
First study of the CP-violating phase and decay-width difference in Bs0→ψ(2S)ϕ decays
2016
A time-dependent angular analysis of Bs0→ψ(2S)ϕ decays is performed using data recorded by the LHCb experiment. The data set corresponds to an integrated luminosity of 3.0fb−1 collected during Run 1 of the LHC. The CP-violating phase and decay-width difference of the Bs0 system are measured to be ϕs=0.23−0.28+0.29±0.02rad and ΔΓs=0.066−0.044+0.041±0.007ps−1, respectively, where the first uncertainty is statistical and the second systematic. This is the first time that ϕs and ΔΓs have been measured in a decay containing the ψ(2S) resonance.
Measurement ofCPviolation inBs0→ϕϕdecays
2014
A measurement of the decay time-dependent CP-violating asymmetry in B-s(0) -> phi phi decays is presented, along with measurements of the T-odd triple-product asymmetries. In this decay channel, the CP-violating weak phase arises from the interference between B-s(0) -(B) over bar (0)(s) mixing and the loop-induced decay amplitude. Using a sample of proton-proton collision data corresponding to an integrated luminosity of 3.0 fb(-1) collected with the LHCb detector, a signal yield of approximately 4000 B-s(0) -> phi phi decays is obtained. The CP-violating phase is measured to be phi(s) = -0.17 +/- 0.15(stat) +/- 0.03(syst) rad. The triple-product asymmetries are measured to be A(U) = -0.003…
Spin asymmetries for events with highpThadrons in DIS and an evaluation of the gluon polarization
2004
We present a measurement of the longitudinal spin cross section asymmetry for deep-inelastic muon-nucleon interactions with two high transverse momentum hadrons in the final state. Two methods of event classification are used to increase the contribution of the photon-gluon fusion process to above 30%. The most effective one, based on a neural network approach, provides the asymmetries A(p)lN(-->)lhhX=0.030+/-0.057(stat)+/-0.010(syst) and A(d)lN(-->)lhhX=0.070+/-0.076(stat)+/-0.010(syst). From these values we derive an averaged gluon polarization DeltaG/G=-0.20+/-0.28(stat)+/-0.10(syst) at an average fraction of nucleon momentum carried by gluons =0.07.