Search results for "Muon"
showing 10 items of 1376 documents
Coherent muon-electron conversion in the dualized standard model
2000
Muon-electron conversion in nuclei is considered in the framework of the Dualized Standard Model. The ratio $B_{\mu-e}$ of the conversion rate to the total muon capture rate is derived, and computed for several nuclei in a parameter-free calculation using parameters previously determined in different physical contexts. The values obtained all lie within the present experimental bounds, but some are so close as to seem readily accessible to experiments already being planned. Similar considerations are applied also to muon-electron conversion in muonium but give rates many orders of magnitude below the present experiment limit.
On the interpretation of the atmospheric neutrino data in terms of flavor changing neutrino interactions
1999
Flavour changing (FC) neutrino-matter interactions have been proposed as a solution to the atmospheric neutrino anomaly. Here we perform the analysis of the full set of the recent 52 kTy Super-Kamiokande atmospheric neutrino data, including the zenith angle distribution of the contained events as well as the higher energy upward-going stopping and through-going muon events. Our results show that the FC mechanism can describe the full data sample with a chi^2_{min}=44/(33 d.o.f) which is acceptable at the 90% confidence level. The combined analysis confines the amount of FC to be either close to maximal or to the level of about (10-50)%.
Golden measurements at a neutrino factory
2000
The precision and discovery potential of a neutrino factory based on muon storage rings is studied. For three-family neutrino oscillations, we analyse how to measure or severely constraint the angle $\theta_{13}$, CP violation, MSW effects and the sign of the atmospheric mass difference $\Delta m^2_{23}$. We present a simple analytical formula for the oscillation probabilities in matter, with all neutrino mass differences non-vanishing, which clarifies the subtleties involved in disentangling the unknown parameters. The appearance of ``wrong-sign muons'' at three reference baselines is considered: 732 km, 3500 km, and 7332 km. We exploit the dependence of the signal on the neutrino energy, …
Performance of the MIND detector at a Neutrino Factory using realistic muon reconstruction
2010
A Neutrino Factory producing an intense beam composed of v(e)((v) over bar (e)) and (v) over bar (mu)(v(mu)) from muon decays has been shown to have the greatest sensitivity to the two currently unmeasured neutrino mixing parameters theta(13) and delta(CP) Using the wrong-sign muon signal to measure v(e)-> v(mu)((v) over bar (e) ->(v) over bar (mu)) oscillations in a 50kt Magnetised Iron Neutrino Detector (MIND) sensitivity to delta(CP) could be maintained down to small values of theta(13) However the detector efficiencies used in these previous studies were calculated assuming perfect pattern recognition In this paper MIND is reassessed taking into account for the first time a realistic pa…
Measurement of σ(pp¯→Z+X)Br(Z→τ+τ−) at s=1.96 TeV
2009
We present a measurement of the cross section for Z boson production times the branching fraction to tau lepton pairs sigma(p (p) over bar -> Z + X)Br(Z -> tau(+)tau(-)) in p (p) over bar collisions at root s = 1.96 TeV. The measurement is performed in the channel in which one tau lepton decays into a muon and neutrinos. and the other tau lepton decays hadronically or into an electron and neutrinos. The data sample corresponds to an integrated luminosity of 1.0 fb(-1) collected with the DO detector at the Fermilab Tevatron Collider. The sample contains 1511 candidate events with an estimated 20% background from jets or muons misidentified as tau leptons. We obtain sigma . Br = 240 +/- 8 (st…
Search for excited muons inpp¯collisions ats=1.96 TeV
2006
We present the results of a search for the production of an excited state of the muon, mu(*), in proton antiproton collisions at root s =1.96 TeV. The data have been collected with the D0 experiment at the Fermilab Tevatron Collider and correspond to an integrated luminosity of approximately 380 pb(-1). We search for mu(*) in the process p (p) over bar ->mu(*)mu, with the mu(*) subsequently decaying to a muon plus photon. No excess above the standard model expectation is observed in data. Interpreting our data in the context of a model that describes mu(*) production by four-fermion contact interactions and mu(*) decay via electroweak processes, we set a 95% confidence level production cros…
The spin of the nucleon in deep inelastic lepton scattering experiments
1992
The current experimental status of the spin dependent structure functions as measured in polarized deep inelastic scattering of charged leptons from nucleons is reviewed. The proposals for new experiments at CERN, SLAC and HERA are discussed with special emphasis on the experiment of the Spin Muon collaboration at CERN which has started data taking.
Tau neutrinos from muon storage rings
2000
Charged tau leptons emerging in a long baseline experiment with a muon storage ring and a far-away detector will positively establish neutrino oscillations. We study the conversion of $\nu_\mu$ ($\bar{\nu}_\mu$) and of $\bar{\nu}_e$ ($\nu_e$) to $\nu_\tau$ or $\bar{\nu}_\tau$ for neutrinos from a 20 GeV muon storage ring, within the strong mixing scheme and on the basis of the squared mass differences which are compatible with all reported neutrino anomalies, including the LSND data. In contrast to other solutions which ignore the Los Alamos anomaly, we find charged tau production rates which should be measurable in a realistic set up. As a consequence, determining the complete mass spectru…
Summary of golden measurements at a ν-factory
2000
The precision and discovery potential of a neutrino factory based on muon storage rings is summarized. For three-family neutrino oscillations, we analyze how to measure or severely constraint the angle $\theta_{13}$, CP violation, MSW effects and the sign of the atmospheric mass difference $\Delta m^2_{23}$. The appearance of ``wrong-sign muons'' at three reference baselines is considered: 732 km, 3500 km and 7332 km. We exploit the dependence of the signal on the neutrino energy, and include as well realistic background estimations and detection efficiencies. The optimal baseline turns out to be $O$(3000 km).
A large magnetic detector for the neutrino factory
2000
Abstract The physics opportunities of the neutrino factory have been the subject of a number of recent studies. It was shown that sensitive measurements of the angle θ 13 , of MSW effects, and of the sign of the atmospheric mass difference Δ m 23 2 are possible, and even CP violation in the neutrino mixing matrix may be within reach. The focus of interest is the oscillation ν e →ν μ , which leads in the well-defined neutrino beam of the neutrino factory to ‘wrong-sign’ muon events. In this paper, we show that a large magnetic detector will be capable of detecting with high efficiency and small backgrounds such wrong-sign muon events. We present a conceptual design of the apparatus and its p…