Search results for "Control system"
showing 10 items of 971 documents
Exploring the intrinsic Lorentz-violating parameters at DUNE
2018
Neutrinos can push our search for new physics to a whole new level. What makes them so hard to be detected, what allows them to travel humongous distances without being stopped or deflected allows to amplify Planck suppressed effects (or effects of comparable size) to a level that we can measure or bound in DUNE. In this work we analyze the sensitivity of DUNE to CPT and Lorentz-violating interactions in a framework that allows a straightforward extrapolation of the bounds obtained to any phenomenological modification of the dispersion relation of neutrinos.
Probing CPT in transitions with entangled neutral kaons
2015
In this paper we present a novel CPT symmetry test in the neutral kaon system based, for the first time, on the direct comparison of the probabilities of a transition and its CPT reverse. The required interchange of in ↔ out states for a given process is obtained exploiting the Einstein-Podolsky-Rosen correlations of neutral kaon pairs produced at a ϕ-factory. The observable quantities have been constructed by selecting the two semileptonic decays for flavour tag, the ππ and 3π 0 decays for CP tag and the time orderings of the decay pairs. The interpretation in terms of the standard Weisskopf-Wigner approach to this system, directly connects CPT violation in these observables to the violati…
New ways to search for right-handed current inB→ρℓν¯decay
2014
An interesting possibility to ease the tension between various determinations of $|{V}_{ub}|$ is to allow a small right-handed contribution to the standard model weak current. The present bounds on such a contribution are fairly weak. We propose new ways to search for such a beyond standard model contribution in semileptonic $B\ensuremath{\rightarrow}\ensuremath{\rho}\ensuremath{\ell}\overline{\ensuremath{\nu}}$ decay. Generalized asymmetries in one, two, or three angular variables are introduced as discriminators, which do not require an unbinned analysis of the fully differential distribution, and a detailed study of the corresponding theoretical uncertainties is performed. A discussion o…
Present and future searches with e^+e^- colliders for the neutral Higgs bosons of the Minimal Supersymmetric Standard Model -- the complete 1-loop an…
1994
New mass regions unexcluded by direct searches are revealed by an analysis of experimental results from LEP1 using full 1-loop diagrammatic calculations of radiative corrections in the MSSM. Simulations of experimental signal efficiencies and background rejection factors, and full 1-loop calculations are combined to study the sensitivity for neutral Higgs bosons at LEP2 and the NLC. Compared with previous studies based on an Effective Potential Approach, we identify mass regions where the discovery potential depends on the MSSM parameters other than the top and stop masses. We propose our method of interpretation to be adopted by the four LEP experiments for better precision. The possibilit…
Tri-bimaximal neutrino mixing and neutrinoless double beta decay
2008
We present a tri-bimaximal lepton mixing scheme where the neutrinoless double beta decay rate (bb0v) has a lower bound which correlates with the ratio alpha = Dmsol/Dmatm well determined by current data, as well as with the unknown Majorana CP phase phi12 characterizing the solar neutrino sub-system. For the special value phi12 = pi/2 (opposite CP-sign neutrinos) the bb0v rate vanishes at tree level when Dmsol/Dmatm = 3/80, only allowed at 3 sigma. For all other cases the rate is nonzero, and lies within current and projected experimental sensitivities close to phi12=0. We suggest two model realizations of this scheme in terms of an A4xZ2 and A4xZ4 flavour symmetries.
Search forWWandWZResonances Decaying to Electron, MissingET, and Two Jets inpp¯Collisions ats=1.96 TeV.
2009
We present a search for WW and WZ production in final states that contain a charged lepton (electron or muon) and at least two jets, produced in {radical}(s)=1.96 TeV pp collisions at the Fermilab Tevatron, using data corresponding to 1.2 fb{sup -1} of integrated luminosity collected with the CDF II detector. Diboson production in this decay channel has yet to be observed at hadron colliders due to the large single W plus jets background. An artificial neural network has been developed to increase signal sensitivity, as compared with an event selection based on conventional cuts. We set a 95% confidence level upper limit of {sigma}{sub WW}xBR(W{yields}l{nu}{sub l},W{yields}jets)+{sigma}{sub…
Electric Dipole Moments in Two-Higgs-Doublet Models
2014
Electric dipole moments are extremely sensitive probes for additional sources of CP violation in new physics models. Specifically, they have been argued in the past to exclude new CP-violating phases in two-Higgs-doublet models. Since recently models including such phases have been discussed widely, we revisit the available constraints in the presence of mechanisms which are typically invoked to evade flavour-changing neutral currents. To that aim, we start by assessing the necessary calculations on the hadronic, nuclear and atomic/molecular level, deriving expressions with conservative error estimates. Their phenomenological analysis in the context of two-Higgs-doublet models yields strong…
New extraction of color-octet NRQCD matrix elements from charmonium hadroproduction
1999
We re-analyze Tavatron data on charmonium hadroproduction in the framework of the color-octet model implemented in the event generator PYTHIA taking into account initial-state radiation of gluons and Altarelli-Parisi evolution of final-state gluons fragmenting into $c\bar{c}$ pairs. We obtain new values for the color-octet matrix elements relevant to this production process. We discuss the sensitivity of our results to the transverse momentum lower cut-off employed in the generation to avoid the problematic $p_t{\to}0$ region, arguing about the reliability of our previous extraction of the NRQCD matrix elements for the $^3S_1^{(8)}$ and $^1S_0^{(8)}+^3P_J^{(8)}$ contributions. Finally we ex…
Magnetic dipole moment of theΔ+(1232)from theγp→γπ0preaction
2001
The $\ensuremath{\gamma}\stackrel{\ensuremath{\rightarrow}}{p}\ensuremath{\gamma}{\ensuremath{\pi}}^{0}p$ reaction in the $\ensuremath{\Delta}(1232)$-resonance region is investigated as a method to access the ${\ensuremath{\Delta}}^{+}(1232)$ magnetic dipole moment. The calculations are performed within the context of an effective Lagrangian model containing both the $\ensuremath{\Delta}$-resonant mechanism and a background of nonresonant contributions to the $\ensuremath{\gamma}\stackrel{\ensuremath{\rightarrow}}{p}\ensuremath{\gamma}{\ensuremath{\pi}}^{0}p$ reaction. Results are shown both for existing and forthcoming $\ensuremath{\gamma}\stackrel{\ensuremath{\rightarrow}}{p}\ensuremath{\…
Golden channel at a neutrino factory revisited: Improved sensitivities from a magnetized iron neutrino detector
2012
This paper describes the performance and sensitivity to neutrino mixing parameters of a Magnetised Iron Neutrino Detector at a Neutrino Factory with a neutrino beam created from the decay of 10 GeV muons. Specifically, it is concerned with the ability of such a detector to detect muons of the opposite sign to those stored (wrong-sign muons) while suppressing contamination of the signal from the interactions of other neutrino species in the beam. A new, more realistic simulation and analysis, which improves the efficiency of this detector at low energies, has been developed using the GENIE neutrino event generator and the GEANT4 simulation toolkit. Low-energy neutrino events down to 1 GeV we…