limits on Physics Beyond the Standard Model from 4 He
نویسندگان
چکیده
A recent analysis of the He abundance determined from observations of extragalactic HII regions indicates a significantly greater uncertainty for the He mass fraction. The derived value is now in line with predictions from big bang nucleosynthesis when the baryon density determined by WMAP is assumed. Based on this new analysis of He, we derive constraints on a host of particle properties which include: limits on the number of relativistic species at the time of BBN (commonly taken to be the limit on neutrino flavors), limits on the variations of fundamental couplings such as αem and GN , and limits on decaying particles.
منابع مشابه
Higgs Physics: from LEP to a Future Linear Collider
New preliminary combined results from the LEP experiments on searches for the Higgs boson beyond the Standard Model are presented. The new determination of the top quark mass at the Tevatron in 2004 influences the interpretations of the LEP results in both, the Standard Model, and the Minimal Supersymmetric extension of the Standard Model. Higgs boson physics will also be a major research area ...
متن کاملضریب گشتاور مغناطیسی لپتون باردار در فضا- زمان ناجابهجایی
The g-factor of the charged leptons has always been considered by many physicists, both experimentaly as well as theoretically. In fact the electron and muon g-factor play the main role in testing the QED as well as the standard model. Meanwhile, there is a discrepancy between the standard model prediction of the muon anomalies magnetic moment and its experimental determination as large as (25...
متن کاملBeyond Standard Model Higgs Boson Physics at the CMS Experiment
Searches for Beyond Standard Model (BSM) Higgs bosons at the CMS experiment are presented. The analyses are based on proton-proton collision data recorded by the CMS experiment at the LHC at CERN at 7 TeV and 8 TeV centre-of-mass energies in the years 2011 and 2012 respectively, corresponding to an integrated luminosity of up to 25 fb−1. No evidence for additional Higgs bosons other than the 12...
متن کاملSearch for physics beyond the standard model in events with two leptons, jets, and missing transverse momentum in pp collisions at sqrt(s) = 8 TeV
A search is presented for physics beyond the standard model in final states with two opposite-sign same-flavor leptons, jets, and missing transverse momentum. The data sample corresponds to an integrated luminosity of 19.4 fb−1 of proton-proton collisions at √ s = 8 TeV collected with the CMS detector at the CERN LHC in 2012. The analysis focuses on searches for a kinematic edge in the invarian...
متن کاملSearch for physics beyond the standard model in events with two leptons, jets, and missing transverse momentum in pp collisions at sqrt(s) = 8 TeV
A search is presented for physics beyond the standard model in final states with two opposite-sign same-flavor leptons, jets, and missing transverse momentum. The data sample corresponds to an integrated luminosity of 19.4 fb−1 of proton-proton collisions at √ s = 8 TeV collected with the CMS detector at the CERN LHC in 2012. The analysis focuses on searches for a kinematic edge in the invarian...
متن کامل