Search results for "Weinberg angle"
showing 10 items of 43 documents
Measurement of the W boson mass
1996
The W boson mass is measured using proton-proton collision data at root s = 13 TeV corresponding to an integrated luminosity of 1.7fb(-1) recorded during 2016 by the LHCb experiment. With a simultaneous fit of the muon q/p(T) distribution of a sample of W ->mu y decays and the phi* distribution of a sample of Z -> mu mu decays the W boson mass is determined to be
Neutrino factory for both large and smallθ13
2008
An analysis of the neutrino oscillation physics capability of a low-energy neutrino factory is presented, including a first simulation of the detector efficiency and event energy threshold. The sensitivity of the physics reach to the presence of backgrounds is also studied. We consider a representative baseline of 1480 km, we use muons with 4.12 GeV energy and we exploit a very conservative estimate of the energy resolution of the detector. Our analysis suggests an impressive physics reach for this setup, which can eliminate degenerate solutions, for both large and small values of the mixing angle {theta}{sub 13}, and can determine leptonic CP violation and the neutrino mass hierarchy with …
MINOS and CPT violating neutrinos
2009
We review the status of CPT violation in the neutrino sector. Apart from LSND, current data favors three flavors of light stable neutrinos and antineutrinos, with both halves of the spectrum having one smaller mass splitting and one larger mass splitting. Oscillation data for the smaller splitting are consistent with CPT. For the larger splitting, current data favor an antineutrino mass-squared splitting that is an order of magnitude larger than the corresponding neutrino splitting, with the corresponding mixing angle less than maximal. This CPT-violating spectrum is driven by recent results from MINOS, but is consistent with other experiments if we ignore LSND. We describe an analysis tech…
Tevatron Run II combination of the effective leptonic electroweak mixing angle
2018
The Ministry of Science and Innovation and the Consolider-Ingenio 2010 Program and the European Union community Marie Curie Fellowship Contract No. 302103.
Decoherence in supernova neutrino transformations suppressed by deleptonization
2007
16 pages, 12 figures.-- PACS nrs.: 14.60.Pq; 97.60.Bw.-- ISI Article Identifier: 000251987300100.-- ArXiv pre-print available at: http://arxiv.org/abs/0706.2498
The weak mixing angle from low energy neutrino measurements: A global update
2016
Taking into account recent theoretical and experimental inputs on reactor fluxes we reconsider the determination of the weak mixing angle from low energy experiments. We perform a global analysis to all available neutrino-electron scattering data from reactor antineutrino experiments, obtaining sin^2(theta_W) = 0.252 \pm 0.030. We discuss the impact of the new theoretical prediction for the neutrino spectrum, the new measurement of the reactor antineutrino spectrum by the Daya Bay collaboration, as well as the effect of radiative corrections. We also reanalyze the measurements of the nu_e-e cross section at accelerator experiments including radiative corrections. By combining reactor and ac…
A Measurement of Sin2-theta-w From the Charge Asymmetry of Hadronic Events At the Z0 Peak
1992
Abstract View references (24)The weak mixing angle has been measured from the charge asymmetry of hadronic events with two different approaches using the DELPHI detector at LEP. Both methods are based on a momentum-weighted charge sum to determine the jet charge in both event hemispheres. In a data sample of 247 300 multihadronic Z0 decays a charge asymmetry of 〈QF〉 - 〈QB〉 = -0.0076±0.0012(stat.)±0.0005(exp. syst.)±0.0014(frag.) and a raw forward-backward asymmetry of Araw FB = -0.0109±0.0020(stat.)±0.0010(exp. syst.)±0.0017(frag.) have been measured. This result corresponds to a value of sinθeff=0.2345±0.0030(exp.)±0.0027(frag.) ,sin2θMS=0.2341±0.0030(exp.)±0. 0027(frag.) and to sin2θW=1-m…
Measurements of the Lineshape of the $Z^{0}$ and Determination of Electroweak Parameters from its Hadronic and Leptonic Decays
1994
Abstract: During the LEP running periods in 1990 and 1991 DELPHI has accumulated approximately 450000 Z0 decays into hadrons and charged leptons. The increased event statistics coupled with improved analysis techniques and improved knowledge of the LEP beam energies permit significantly better measurements of the mass and width of the Z0 resonance. Model independent fits to the cross sections and leptonic forward-backward asymmetries yield the following Z0 parameters: the mass and total width M(Z) = 91.187 +/- 0.009 GeV, GAMMA(Z) = 2.486 +/- 0.012 GeV, the hadronic and leptonic partial widths GAMMA(had) = 1.725 +/- 0.012GeV, GAMMA(l) = 83.01 +/- 0.52 MeV, the invisible width GAMMA(inv) = 51…
Consistent searches for SMEFT effects in non-resonant dijet events
2018
We investigate the bounds which can be placed on generic new-physics contributions to dijet production at the LHC using the framework of the Standard Model Effective Field Theory, deriving the first consistently-treated EFT bounds from non-resonant high-energy data. We recast an analysis searching for quark compositeness, equivalent to treating the SM with one higher-dimensional operator as a complete UV model. In order to reach consistent, model-independent EFT conclusions, it is necessary to truncate the EFT effects consistently at order $1/\Lambda^2$ and to include the possibility of multiple operators simultaneously contributing to the observables, neither of which has been done in prev…
A Precise Measurement of the $\tau$ Polarisation at LEP-1
2000
The $\tau$ polarisation has been studied with the ${\rm e^+e^-}\to \tau^+\tau^-$ data collected by the DELPHI detector at LEP in 1993, 1994 and 1995 around the Z resonance firstly through the exclusive decay channels ${\rm e}\nu\bar{\nu}$ , $\mu\nu\bar{\nu}$ , $\pi\nu$ , $\rho\nu$ and ${\rm a}_1\nu$ and secondly with an inclusive hadronic analysis which benefits from a higher efficiency and a better systematic precision. The results have been combined with those previously published on 1990 to 1992 DELPHI data, to produce results which reflect the full LEP-1 statistics. The fit of the $\tau$ polarisation dependence on the production angle yielded the polarisation parameters ${\cal A}_{_{\sc…