121374094
T2K: A LONG-BASELINE EXPERIMENT TO STUDY NEUTRINOS
T2K is the first of a new generation of long baseline neutrino oscillation experiments that will measure neutrino oscillations parameters. The experiment uses the J-PARC accelerator complex on the east cost of Japan to sent a neutrino beam to the Kamioka mine, located 295 km to the west. It consists of a dedicated beam-line, a near detector complex to characterize the beam and the well-known Super-Kamiokande detector to measure the oscillation signal. This paper describes the experimental setup, the results of the first measurement campaign as well as giving an outlook on the future potential of the experiment.
123663776
The NuMI off-axis long baseline experiment
Several different experiments have now established that neutrinos do oscillate or may have presented experimental evidence that can be explained by neutrino oscillations [1,2,3,4,5]. The purpose of future experiments is now to measure with high precision the parameters of the neutrino mixing or so-called MNS matrix. One of those experiments is planned at the powerful NuMI neutrino beam line. The experiment is especially designed to obtain a high sensitivity for electron neutrino appearance in a muon neutrino beam. This measurement is related to the mixing angle Θ13, which is so far undetermined from previous measurements. This article will report on possible technology choices and the physics reach of the experiment.
1135757
Status of the LBL oscillation experiments MINOS and OPERA
MINOS and OPERA will be the next generation long baseline neutrino experiments to measure neutrino oscillations as suggested by the Super-Kamiokande atmospheric neutrino results in a well controlled environment. Neutrinos produced by the Fermilab main injector will be measured by the two MINOS detectors. A near detector will be located at the Fermilab site to measure the neutrino beam composition at production, a far detector will measure it after oscillation may have modified the beam composition. OPERA will be located in the Grand Sasso underground laboratory and search for the appearance of tau neutrinos in a muon neutrino beam produced at the CERN SPS. By chance, the baseline is 735 km for both experiments.
123519082
MINOS the main injector neutrino oscillation search
Abstract MINOS is a neutrino experiment which uses a beam of neutrinos from the Fermilab main injector to determine the parameters of possible neutrino oscillations. It consists of two detectors: a near detector to measure the beam composition at the production site and a far detector 730 km away to re-measure the composition and detect any oscillation which may have occurred. MINOS is a tracking calorimeter build from solid plastic scintillators to measure all the neutrino interactions.
25404962
Low background anti-neutrino monitoring with an innovative composite solid scintillator detector
The detection of anti-neutrinos from nuclear reactors at close stand-off is a challenging measurement. The requirements for a remote monitoring device that could be used for close stand-off reactor core monitoring is difficult to meet with standard liquid scintillator technologies. Due to the low rate of anti-neutrinos detectable within 10 m from research reactors the detection efficiency has to be as high as possible with a relatively compact and safe design. The more practical aspects of the system are usually difficult to meet because these systems have to be deployed at low overburden where reactor gamma-ray and neutron backgrounds are a few orders of magnitude higher than the anti-neutrino rate. Large and costly passive shielding is usually needed to reduce these backgrounds closer to the anti-neutrino rate (typically 10-4 Hz/tonne). A novel approach to measuring reactor anti-neutrinos was developed based on composite Polyvynil-Toluene and 6LiF:ZnS(Ag) scintillators. The system is highly segmented and read out by a network of wavelength shifting fibers and MPPCs which enables accurate localization of the outgoing positron and neutron. This more precise imaging of the interaction help with discriminating backgrounds and thus limits the required passive shielding around the detector. We report the expected performance from a Geant4 Monte-Carlo simulation of the system and the test of a 8 kg active mass prototype deployed at the BR2 reactor in Mol, Belgium. Measurements of the reactor on and off backgrounds rates and energy spectrum of signal candidates are presented using data collected at BR2 during summer 2013.
119108691
Combining neutrino oscillation experiments with the Feldman–Cousins method
In this paper we describe how two or more experimental results can be combined within the procedure of Feldman and Cousins, to provide combined confidence limits on the physical parameters of interest. We demonstrate the technique by combining the recent electron neutrino appearance results from T2K and MINOS. Our best fit point is sin2 2θ13 = 0.08 (0.11) and δ = 1.1 (2.0)π; in addition we exclude sin2 2θ13 = 0 at 2.7σ (2.8σ) for the normal (inverted) neutrino mass hierarchy.
119407344
Bound States in Yukawa Theory
A generalization of the Gell-Mann–Low Theorem is applied to lowest nontrivial order to bound state calculations in Yukawa theory. We present the solution of the corresponding effective Schrödinger equation for two-fermion bound states with the exchange of a massless boson. The complete low-lying bound state spectrum is obtained for fine structure constants below one and different ratios of the constituent masses. The consistency of the nonrelativistic and one-body limits is explicitly verified.
1560396
Dimensional reduction, hard thermal loops, and the renormalization group
We study the realization of dimensional reduction and the validity of the hard thermal loop expansion for lambda phi^4 theory at finite temperature, using an environmentally friendly finite-temperature renormalization group with a fiducial temperature as flow parameter. The one-loop renormalization group allows for a consistent description of the system at low and high temperatures, and in particular of the phase transition. The main results are that dimensional reduction applies, apart from a range of temperatures around the phase transition, at high temperatures (compared to the zero temperature mass) only for sufficiently small coupling constants, while the HTL expansion is valid below (and rather far from) the phase transition, and, again, at high temperatures only in the case of sufficiently small coupling constants. We emphasize that close to the critical temperature, physics is completely dominated by thermal fluctuations that are not resummed in the hard thermal loop approach and where universal quantities are independent of the parameters of the fundamental four-dimensional theory.
119161167
Perturbation theory in the Hamiltonian approach to Yang-Mills theory in Coulomb gauge
We study the Hamiltonian approach to Yang-Mills theory in Coulomb gauge in Rayleigh-Schroedinger perturbation theory. The static gluon and ghost propagator as well as the potential between static color sources are calculated to one-loop order. Furthermore, the one-loop {beta} function is calculated from both the ghost-gluon vertex and the static potential and found to agree with the result of covariant perturbation theory.
119200310
Color Coulomb potential in Yang-Mills theory from Hamiltonian flows
We consider the Hamiltonian formulation of Yang-Mills theory in the Coulomb gauge and apply the recently developed technique of Hamiltonian flows. We formulate a flow equation for the color Coulomb potential which allows for a scaling solution that results in an almost linearly rising confining potential.
118885765
Functional approaches to infrared Yang-Mills theory in the Coulomb gauge
We present the current status of ongoing efforts to use functional methods, Dyson-Schwinger equations and functional renormalization group equations, for the description of the infrared regime of nonabelian (pure) gauge theories. In particular, we present a new determination of the color-Coulomb potential with the help of the functional renormalization group that results in an almost linearly rising potential between static color charges at large spatial distances.