Search results for " Detectors"
showing 10 items of 2027 documents
Status of four-neutrino mass schemes: a global and unified approach to current neutrino oscillation data
2001
We present a unified global analysis of neutrino oscillation data within the framework of the four-neutrino mass schemes (3+1) and (2+2). We include all data from solar and atmospheric neutrino experiments, as well as information from short-baseline experiments including LSND. If we combine only solar and atmospheric neutrino data, (3+1) schemes are clearly preferred, whereas short-baseline data in combination with atmospheric data prefers (2+2) models. When combining all data in a global analysis the (3+1) mass scheme gives a slightly better fit than the (2+2) case, though all four-neutrino schemes are presently acceptable. The LSND result disfavors the three-active neutrino scenario with …
Borexino as a test of solar matter density fluctuations
1997
This talk summarizes some results of our recent work focusing on the possibility to test solar matter density fluctuations by the future Borexino experiment.
More on higher order decays of the lighter top squark
1999
We discuss the three-body decays stop_1 -> W^+ b neutralino_1, stop_1 -> H^+ b neutralino_1, stop_1 -> b slepton_i neutrino_l, and stop_1 -> b sneutrino_l l^+$ ($l =e,��,��$) of the lighter top squark within the minimal supersymmetric standard model. We give the complete analytical formulas for the decay widths and present a numerical study in view of an upgraded Tevatron, the CERN LHC, and a future lepton collider demonstrating the importance of these decay modes.
Is charged lepton flavor violation a high energy phenomenon?
2013
Searches for rare processes such as mu --> e gamma put stringent limits on lepton flavour violation expected in many Beyond the Standard Model physics scenarios. This usually precludes the observation of flavour violation at high energy colliders such as the LHC. We here discuss a scenario where right-handed neutrinos are produced via a Z' portal but which can only decay via small flavour violating couplings. Consequently, the process rate is unsuppressed by the small couplings and can be visible despite unobservably small mu --> e gamma rates.
Testing the Zee-Babu model via neutrino data, lepton flavour violation and direct searches at the LHC
2014
We discuss how the Zee-Babu model can be tested combining information from neutrino data, low-energy experiments and direct searches at the LHC. We update previous analysis in the light of the recent measurement of the neutrino mixing angle $\theta_{13}$, the new MEG limits on $\mu \rightarrow e \gamma$, the lower bounds on doubly-charged scalars coming from LHC data, and, of course, the discovery of a 125 GeV Higgs boson by ATLAS and CMS. In particular, we find that the new singly- and doubly-charged scalars are accessible at the second run of the LHC, yielding different signatures depending on the neutrino hierarchy and on the values of the phases. We also discuss in detail the stability …
Experimental tests for the Babu-Zee two-loop model of Majorana neutrino masses
2006
The smallness of the observed neutrino masses might have a radiative origin. Here we revisit a specific two-loop model of neutrino mass, independently proposed by Babu and Zee. We point out that current constraints from neutrino data can be used to derive strict lower limits on the branching ratio of flavour changing charged lepton decays, such as $\mu \to e \gamma$. Non-observation of Br($\mu \to e \gamma$) at the level of $10^{-13}$ would rule out singly charged scalar masses smaller than 590 GeV (5.04 TeV) in case of normal (inverse) neutrino mass hierarchy. Conversely, decay branching ratios of the non-standard scalars of the model can be fixed by the measured neutrino angles (and mass …
A neutrino apparatus with improved capabilities for a short baseline νμ(νe) ↔ ντ search
1995
Abstract We propose the conceptual design of a Neutrino ApparatUS with Improved CApAbilities (NAUSICAA). This detector could be used for a new, short-baseline, high sensitivity νμ(νe) ↔ ντ oscillation search experiment at the CERN-SPS neutrino beam, as well as at the future Fermilab Main Injector neutrino beam. The heart of the detector is a finely instrumented target, made of a sandwich of a light Z material and high resolution tracking detectors. Downstream of the target there are tracking detectors for momentum measurement, followed by a compensating calorimeter. All these systems are contained within magnet providing a magnetic field of about 1 T. Following the magnet there is a muon de…
Ultra-long-lived particles searches with MATHUSLA
2018
Abstract There are many theoretical motivations for long-lived particle (LLP) signals at the LHC in a comprehensive survey of Standard Model (SM) extensions. LLPs are a common prediction of a wide range of theories that address unsolved fundamental mysteries such as naturalness, dark matter, baryogenesis and neutrino masses, and represent a natural and generic possibility for physics beyond the SM (BSM). MATHUSLA (MAssive Timing Hodoscope for Ultra Stable neutraL pArticles) is a proposal for a minimally instrumented, large-volume surface detector to detect such LLPs. The MATHUSLA surface detector will consist of an air-filled decay volume surrounded by charged particles detectors (top, bott…
Diboson production in proton–proton collisions at $\sqrt{s} = 7~{\rm TeV}$
2014
This review article summarizes results on the production cross section measurements of electroweak boson pairs ($WW$, $WZ$, $ZZ$, $W\gamma$ and $Z\gamma$) at the Large Hadron Collider (LHC) in $pp$ collisions at a center-of-mass energy of $\sqrt{s}=7$ \TeV. The two general-purpose detectors at the LHC, ATLAS and CMS, recorded an integrated luminosity of $5fb^{-1}$ in 2011, which offered the possibility to study the properties of diboson production to high precision. These measurements test predictions of the Standard Model (SM) in a new energy regime and are crucial for the understanding and the measurement of the SM Higgs boson and other new particles. In this review, special emphasis is d…
ATLAS Tile Calorimeter performance with Run 1 data
2016
Abstract The performance of the central hadronic calorimeter, TileCal, in the ATLAS Experiment at the Large Hadron Collider is studied using cosmic-ray muons and the large sample of proton-proton collisions acquired during the Run 1 of LHC (2010–2012). Results are presented for the precision of the absolute energy scale and timing, noise characterization, and time-stability of the detector. The results show that the Tile Calorimeter performance is within the design requirements of the detector.