Search results for "Electroweak"
showing 10 items of 744 documents
Probing nonstandard neutrino-electron interactions with solar and reactor neutrinos
2009
Most neutrino mass extensions of the standard electroweak model entail non-standard interactions which, in the low energy limit, can be parametrized in term of effective four-fermion operators $\nu_\alpha \nu_\beta \bar f f $. Typically of sub-weak strength, $\epsilon_{\alpha \beta} G_F$, these are characterized by dimensionless coupling parameters, $\epsilon_{\alpha \beta}$, which may be relatively sizeable in a wide class of schemes. Here we focus on non-universal (NU) flavor conserving couplings ($\alpha = \beta$) with electrons ($f = e$) and analyse their impact on the phenomenology of solar neutrinos. We consistently take into account their effect both at the level of propagation where…
The lifetime of unstable particles in electromagnetic fields
2007
We show that the electromagnetic moments of unstable particles (resonances) have an absorptive contribution which quantifies the change of the particle's lifetime in an external electromagnetic field. To give an example we compute here the imaginary part of the magnetic moment for the cases of the muon and the neutron at leading order in the electroweak coupling. We also consider an analogous effect for the strongly-decaying $\Delta$(1232) resonance. The result for the muon is Im$ \mu = e G_F^2 m^3/768 \pi^3$, with $e$ the charge and $m$ the mass of the muon, $G_F$ the Fermi constant, which in an external magnetic field of $B$ Tesla give rise to the relative change in the muon lifetime of $…
A glimpse of heavy scales through the electroweak resonance theory
2018
El Modelo Est´andar (Standard Model, SM) de f´ısica de part´ıculas representa el mejor marco te´orico para describir el mundo subat´omico. Su importancia radica en que nos ha permitido adentrarnos en un nuevo nivel m´as profundo de la realidad f´ısica y del mundo que nos rodea. En el an˜o 2012, fue confirmada la u´ltima part´ıcula fundamental que completaba el modelo, el bos´on de Higgs, en el Large Hadron Collider (LHC) y en la actualidad no hay ninguna evidencia de ninguna nueva part´ıcula ex´otica ni de ninguna desviaci´on significativa de algu´n par´ametro de la teor´ıa (las masas de los neutrinos pueden ser incluidas f´acilmente). Adem´as, son ya numerosos los modelos de altas energ´ıa…
"Exclusion contour aux 1 (Exp.)" of "Search for direct stau production in events with two hadronic $\tau$-leptons in $\sqrt{s} = 13$ TeV $pp$ collisi…
2020
Expected 95% CL exclusion limits for simplified models with direct stau pair production in SR-lowMass.
"Exclusion contour aux 1 (Obs.)" of "Search for direct stau production in events with two hadronic $\tau$-leptons in $\sqrt{s} = 13$ TeV $pp$ collisi…
2020
Observed 95% CL exclusion limits for simplified models with direct stau pair production in SR-lowMass.
"Exclusion contour 1 (Obs.)" of "Search for direct stau production in events with two hadronic $\tau$-leptons in $\sqrt{s} = 13$ TeV $pp$ collisions …
2020
The observed 95\% CL exclusion contours for the combined fit of SR-lowMass and SR-highMass for simplified models with combined ${\tilde{\tau}}^{+}_{R,L} {\tilde{\tau}}^{-}_{R,L}$ production.
"Exclusion contour 2 (Exp.)" of "Search for direct stau production in events with two hadronic $\tau$-leptons in $\sqrt{s} = 13$ TeV $pp$ collisions …
2020
The expected 95% CL exclusion contours for the combined fit of SR-lowMass and SR-highMass for simplified models with ${\tilde{\tau}}_L {\tilde{\tau}}_L$ only production.
"Exclusion contour aux 2 (Obs.)" of "Search for direct stau production in events with two hadronic $\tau$-leptons in $\sqrt{s} = 13$ TeV $pp$ collisi…
2020
Observed 95% CL exclusion limits for simplified models with direct stau pair production in SR-highMass.
"Exclusion contour aux 2 (Exp.)" of "Search for direct stau production in events with two hadronic $\tau$-leptons in $\sqrt{s} = 13$ TeV $pp$ collisi…
2020
Expected 95% CL exclusion limits for simplified models with direct stau pair production in SR-highMass.
"Exclusion contour 2 (Obs.)" of "Search for direct stau production in events with two hadronic $\tau$-leptons in $\sqrt{s} = 13$ TeV $pp$ collisions …
2020
The observed 95% CL exclusion contours for the combined fit of SR-lowMass and SR-highMass for simplified models with ${\tilde{\tau}}_L {\tilde{\tau}}_L$ only production.