Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new userResults from the MINOS Experiment and New MINOS+ Data
112
0
0.0
(
0
)
Authors
A. Holin
Ask ChatGPT about the research
No Arabic abstract
The MINOS experiment took data for seven years between May 2005 and April 2012. Since then it has been reborn as the new MINOS+ experiment in the upgraded medium energy NuMI beam and started taking data in September 2013. An update to the MINOS standard oscillations three-flavour disappearance analysis is presented which includes 28% more atmospheric neutrino data. This combined three-flavour analysis calculates an atmospheric parameter best-fit point of $Delta m_{32}^{2}=2.37^{+0.11}_{-0.07} times 10^{-3}$~eV$^{2}$ and $sin^{2}theta_{23}=0.43^{+0.19}_{-0.05}$ for the inverted hierarchy, for which the MINOS fit shows a slight preference. A first look at the new MINOS+ beam data is presented. The new data is consistent with the combined three-flavour analysis. Finally, new MINOS results for the search for sterile neutrinos using neutrino disappearance are shown which cut out a significant amount of the allowed phase space for a sterile neutrino to exist.
rate research
Read More
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 $ u_mu to u_e$ conversion. The focus will be on the analysis of data for $ u_mu to u_e$ conversion. Using data from an exposure of $3.14times 10^{20}$ 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 $27pm 5(stat)pm 2(syst)$. 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.
The MINOS experiment is a long-baseline neutrino experiment designed to study neutrino behaviour, in particular the phenomenon of neutrino oscillations. MINOS sends the NuMI neutrino beam through two detectors, a Near Detector 1 km downstream from the beam source at Fermilab, and a Far Detector 735 km away in the Soudan Mine in Minnesota. MINOS has been taking beam data since 2005. This document summarises recent neutrino oscillations results, with particular emphasis on electron neutrino appearance, which probes the angle $theta_{13}$ of the neutrino mass mixing matrix. For an exposure of 8.2$times 10^{20}$ protons on target, MINOS finds that $sin^{2}(2theta_{13})<0.12$ for the normal mass hierarchy, and $<0.20$ for the inverted mass hierarchy at the 90% C.L., if the CP-violating phase $delta=0$.
We report the final measurement of the neutrino oscillation parameters $Delta m^2_{32}$ and $sin^2theta_{23}$ using all data from the MINOS and MINOS+ experiments. These data were collected using a total exposure of $23.76 times 10^{20}$ protons on target producing $ u_{mu}$ and $overline{ u_mu}$ beams and 60.75 kt$cdot$yr exposure to atmospheric neutrinos. The measurement of the disappearance of $ u_{mu}$ and the appearance of $ u_e$ events between the Near and Far detectors yields $|Delta m^2_{32}|=2.40^{+0.08}_{-0.09}~(2.45^{+0.07}_{-0.08}) times 10^{-3}$ eV$^2$ and $sin^2theta_{23} = 0.43^{+0.20}_{-0.04} ~(0.42^{+0.07}_{-0.03})$ at 68% C.L. for Normal (Inverted) Hierarchy.
The MINOS experiment ran from 2003 until 2012 and collected a data sample including 10.71x10^20 protons-on-target (POT) of beam neutrinos, 3.36x10^20 POT of beam antineutrinos and an atmospheric neutrino exposure of 37.88 kt-yrs. The final measurement of the atmospheric neutrino oscillation parameters, dm^2_32 and theta_23, came from a full three flavour oscillation analysis of the combined CC nu_mu and CC anti-nu_mu beam and atmospheric samples and the CC nu_e and CC anti-nu_e appearance samples. This analysis yielded the most precise measurement of the atmospheric mass splitting dm^2_32 performed to date. The results are |dm^2_32|=[2.28 - 2.46]x10^-3 eV^2 (68%) and sin^{2}theta_23=0.35-0.65$ (90%) in the normal hierarchy, and |dm^2_32|=[2.32 - 2.53]x10^-3 eV^2 (68%) and sin^{2}theta_23=0.34-0.67 (90%) in the inverted hierarchy. The successor to MINOS in the NOvA era at FNAL, MINOS+, is now collecting data mostly in the 3-10 GeV region, and an analysis of nu_mu disappearance using the first 2.99x10^20 POT of data produced results very consistent with those from MINOS. Future data will further test the standard neutrino oscillation paradigm and allow for improved searches for exotic phenomena including sterile neutrinos, large extra dimensions and non-standard interactions.
We report new constraints on the size of large extra dimensions from data collected by the MINOS experiment between 2005 and 2012. Our analysis employs a model in which sterile neutrinos arise as Kaluza-Klein states in large extra dimensions and thus modify the neutrino oscillation probabilities due to mixing between active and sterile neutrino states. Using Fermilabs NuMI beam exposure of $10.56 times 10^{20}$ protons-on-target, we combine muon neutrino charged current and neutral current data sets from the Near and Far Detectors and observe no evidence for deviations from standard three-flavor neutrino oscillations. The ratios of reconstructed energy spectra in the two detectors constrain the size of large extra dimensions to be smaller than $0.45,mutext{m}$ at 90% C.L. in the limit of a vanishing lightest active neutrino mass. Stronger limits are obtained for non-vanishing masses.
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
