Recent Results from the MINOS experiment

MINOS is an accelerator neutrino oscillation experiment at Fermilab. An intense high energy neutrino beam is produced at Fermilab and sent to a near detector on the Fermilab site and also to a 5 kTon far detector 735 km away in the Soudan mine in northern Minnesota. The experiment has now had several years of running with millions of events in the near detector and hundreds of events recorded in the far detector. I will report on the recent results from this experiment which include precise measurement of $|\Delta m^2_{32}|$, ~analysis of neutral current data to limit the component of sterile neutrinos, and the search for $\nu_\mu \to \nu_e$ conversion. The focus will be on the analysis of data for $\nu_\mu \to \nu_e$ conversion. Using data from an exposure of $3.14\times 10^{20}$ protons on target, we have selected electron type events in both the near and the far detector. The near detector is used to measure the background which is extrapolated to the far detector. We have found 35 events in the signal region with a background expectation of $27\pm 5(stat)\pm 2(syst)$. Using this observation we set a 90% C.L. limit of $\sin^2 2 \theta_{13} < 0.29$ for $\delta_{cp} = 0$ and normal mass hierarchy. Further analysis is under way to reduce backgrounds and improve sensitivity.Comment: This was prepared for the proceedings of the XIII International Workshop on Neutrino Telescopes at the Istituto Veneto di Scienze, Lettere ed Arti in Venice, Italy held on March 10-13, 2009. The presentation was on behalf of the MINOS collaboratio

Muon Decay Asymmetries from KL0→π0μ+μ−K^0_L \to \pi^0 \mu^+ \mu^- Decays

We have examined the decay $K^0_L \to \pi^0 \mu^+ \mu^-$ in which the branching ratio, the muon energy asymmetry and the muon decay asymmetry could be measured. In particular, we find that within the Standard Model the longitudinal polarization ($P_L$) of the muon is proportional to the direct CP violating amplitude. On the other hand the energy asymmetry and the out-of-plane polarization ($P_N$) depend on both indirect and direct CP violating amplitudes. Although the branching ratio is small and difficult to measure because of background, the asymmetries could be large $\cal{O}$(1) in the Standard Model. A combined analysis of the energy asymmetry, $P_L$ and $P_N$ could be used to separate indirect CPV, direct CPV, and CP conserving contributions to the decay.Comment: 6 pages, 4 figures, To be Published in Physical Review

Status of the MINOS experiment

I will present the status of the long baseline neutrino oscillation experiment MINOS at Fermi National Accelerator Laboratory (Fermilab). I will summarize the status of the detector and beam construction, the expected event rates and sensitivity to physics. I will also comment on possible future plans to improve the performance of the experiment.Comment: Invited talk at the Seventh International Workshop on Tau Lepton Physics (TAU02), Santa Cruz, Ca, USA, Sept 2002, 7 pages, 6 figures, LaTeX Higher res figures at http://minos.phy.bnl.gov/~diwan/tau02_th08.p

Forward production of prompt neutrinos from charm in the atmosphere and at high energy colliders

The high-energy atmospheric neutrino flux is dominated by neutrinos from the decays of charmed hadrons produced in the forward direction by cosmic ray interactions with air nuclei. We evaluate the charm contributions to the prompt atmospheric neutrino flux as a function of the center-of-mass energy √ of the hadronic collision and of the center-of-mass rapidity y of the produced charm hadron. Uncertainties associated with parton distribution functions are also evaluated as a function of . We find that the y coverage of LHCb for forward heavy-flavour production, complemented by the angular coverage of present and future forward neutrino experiments at the LHC, bracket the most interesting regions for the prompt atmospheric neutrino flux. At √ = 14 TeV foreseen for the HL-LHC phase, nucleon collisions in air contribute to the prompt neutrino flux prominently below _ ~ 10⁷ GeV. Measurements of forward charm and/or forward neutrinos produced in hadron collisions up to √ = 100 TeV, which might become possible at the FCC, are relevant for the prompt atmospheric neutrino flux up to _ = 108 GeV and beyond