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Register a new userConstraints on Large Extra Dimensions from the MINOS Experiment
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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.
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We reconsider cosmological constraints on extra dimension theories from the excess production of Kaluza-Klein gravitons. We point out that, if the normalcy temperature is above 1 GeV, then graviton states produced at this temperature will decay early enough that they do not affect the present day dark matter density, or the diffuse gamma ray background. We rederive the relevant cosmological constraints for this scenario.
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.
The holographic principle asserts that the entropy of a system cannot exceed its boundary area in Planck units. However, conventional quantum field theory fails to describe such systems. In this Letter, we assume the existence of large $n$ extra dimensions and propose a relationship between UV and IR cutoffs in this case. We find that if $n=2$, this effective field theory could be a good description of holographic systems. If these extra dimensions are detected in future experiments, it will help to prove the validity of the holographic principle. We also discuss implications for the cosmological constant problem.
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.
We investigate the potential of the long-baseline Deep Underground Neutrino Experiment (DUNE) to study large-extra-dimension (LED) models originally proposed to explain the smallness of neutrino masses by postulating that right-handed neutrinos, unlike all standard model fermion fields, can propagate in the bulk. The massive Kaluza-Klein (KK) modes of the right-handed neutrino fields modify the neutrino oscillation probabilities and can hence affect their propagation. We show that, as far as DUNE is concerned, the LED model is indistinguishable from a $(3 + 3N)$-neutrino framework for modest values of $N$; $N$ = 1 is usually a very good approximation. Nonetheless, there are no new sources of $CP$-invariance violation other than one $CP$-odd phase that can be easily mapped onto the $CP$-odd phase in the standard three-neutrino paradigm. We analyze the sensitivity of DUNE to the LED framework, and explore the capability of DUNE to differentiate the LED model from the three-neutrino scenario and from a generic $(3 + 1)$-neutrino model.
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