The reactor neutrino and gallium anomalies can be tested with a 3-4 PBq
(75-100 kCi scale) 144Ce-144Pr antineutrino beta-source deployed at the center
or next to a large low-background liquid ...scintillator detector. The
antineutrino generator will be produced by the Russian reprocessing plant PA
Mayak as early as 2014, transported to Japan, and deployed in the Kamioka
Liquid Scintillator Anti-Neutrino Detector (KamLAND) as early as 2015.
KamLAND's 13 m diameter target volume provides a suitable environment to
measure the energy and position dependence of the detected neutrino flux. A
characteristic oscillation pattern would be visible for a baseline of about 10
m or less, providing a very clean signal of neutrino disappearance into a
yet-unknown, sterile neutrino state. This will provide a comprehensive test of
the electron dissaperance neutrino anomalies and could lead to the discovery of
a 4th neutrino state for Delta_m^2 > 0.1 eV^2 and sin^2(2theta) > 0.05.
Transverse momentum spectra of pions, kaons, protons and antiprotons from Au+Au collisions at sqrt(s_(NN)) = 62.4 GeV have been measured by the PHOBOS experiment at the Relativistic Heavy Ion ...Collider at Brookhaven National Laboratory. The identification of particles relies on three different methods: low momentum particles stopping in the first detector layers; the specific energy loss (dE/dx) in the silicon Spectrometer, and Time-of-Flight measurement. These methods cover the transverse momentum ranges 0.03-0.2, 0.2-1.0 and 0.5-3.0 GeV/c, respectively. Baryons are found to have substantially harder transverse momentum spectra than mesons. The pT region in which the proton to pion ratio reaches unity in central Au+Au collisions at sqrt(s_(NN)) = 62.4 GeV fits into a smooth trend as a function of collision energy. At low transverse momenta, the spectra exhibit a significant deviation from transverse mass scaling, and when the observed particle yields at very low pT are compared to extrapolations from higher pT, no significant excess is found. By comparing our results to Au+Au collisions at sqrt(s_(NN)) = 200 GeV, we conclude that the net proton yield at midrapidity is proportional to the number of participant nucleons in the collision.
We have measured the neutron structure function
g
2
n
and the virtual photon-nucleon asymmetry
A
2
n
over the kinematic range 0.014 ⩽ × ⩽ 0.7 and 1.0 ⩽
Q
2
⩽ 17.0 by scattering 48.3 GeV ...longitudinally polarized electrons from polarized
3He. Results for
A
2
n
are significantly smaller than the √
R positivity limit over most of the measured range and data for
g
2
n
are generally consistent with the twist-2 Wandzura-Wilczek prediction. Using our measured
g
2
n
we obtain results for the twist-3 reduced matrix element
d
2
n
, and the integral ∫
g
2
n
(
x)
dx in the range 0.014 ⩽ × ⩽ 1.0. Data from this experiment are combined with existing data for
g
2
n
to obtain an average for
d
2
n
and the integral ∫
g
2
n
(
x)
dx.
Two-particle correlations of identical charged pion pairs from Au+Au collisions at {radical}(s{sub NN})=62.4 and 200 GeV were measured by the PHOBOS experiment at BNL Relativistic Heavy Ion Collider ...(RHIC). Data for the 15% most central events were analyzed with Bertsch-Pratt and Yano-Koonin-Podgoretskii parametrizations using pairs with rapidities of 0.4<y{sub {pi}}{sub {pi}}<1.3 and transverse momenta 0.1<k{sub T}<1.4 GeV/c. The Bertsch-Pratt radii R{sub o} and R{sub l} decrease as a function of pair transverse momentum. R{sub o} and R{sub s} are independent of collision energy, while R{sub l} shows a slight increase. The source rapidity y{sub YKP} scales roughly with the pair rapidity y{sub {pi}}{sub {pi}}, indicating strong dynamical correlations.
This Rapid Communication describes the measurement of elliptic flow for charged particles in Au+Au collisions at {radical}(s{sub NN})=200 GeV using the PHOBOS detector at the Relativistic Heavy Ion ...Collider. The measured azimuthal anisotropy is presented over a wide range of pseudorapidity for three broad collision centrality classes for the first time at this energy. Two distinct methods of extracting the flow signal were used to reduce systematic uncertainties. The elliptic flow falls sharply with increasing |{eta}| at 200 GeV for all the centralities studied, as observed for minimum-bias collisions at {radical}(s{sub NN})=130 GeV.
We have measured the beam-normal single-spin asymmetry \(A_n\) in the elastic scattering of 1-3 GeV transversely polarized electrons from \(^1\)H and for the first time from \(^4\)He, \(^{12}\)C, and ...\(^{208}\)Pb. For \(^1\)H, \(^4\)He and \(^{12}\)C, the measurements are in agreement with calculations that relate \(A_n\) to the imaginary part of the two-photon exchange amplitude including inelastic intermediate states. Surprisingly, the \(^{208}\)Pb result is significantly smaller than the corresponding prediction using the same formalism. These results suggest that a systematic set of new \(A_n\) measurements might emerge as a new and sensitive probe of the structure of heavy nuclei.
The measured pseudorapidity distributions of primary charged particles over a wide pseudorapidity range of |{eta}|{<=}5.4 and integrated charged particle multiplicities in d+Au collisions at ...{radical}(s{sub NN})=200 GeV are presented as a function of collision centrality. The longitudinal features of d+Au collisions at {radical}(s{sub NN})=200 GeV are found to be very similar to those seen in p+A collisions at lower energies. The total multiplicity of charged particles is found to scale with the total number of participants according to N{sub ch}{sup dAu}=(1/2)<N{sub part}>N{sub ch}{sup pp}, and the energy dependence of the density of charged particles produced in the fragmentation region exhibits extended longitudinal scaling.
The production of neutral pions in 158AGeV Pb+Pb collisions has been studied in the WA98 experiment at the CERN SPS. Transverse momentum spectra are studied for the range 0.3 GeV/c mT-m0 4.0 GeV/c. ...The results for central collisions are compared to various models. The centrality dependence of the neutral pion spectral shape and yield is investigated. An invariance of the spectral shape and a simple scaling of the yield with the number of participating nucleons is observed for centralities with greater than about 30 participating nucleons which is most naturally explained by assuming an equilibrated system.
We propose to test for short baseline neutrino oscillations, implied by the recent reevaluation of the reactor antineutrino flux and by anomalous results from the gallium solar neutrino detectors. ...The test will consist of producing a 75 kCi 144Ce - 144Pr antineutrino source to be deployed in the Kamioka Liquid Scintillator Anti-Neutrino Detector (KamLAND). KamLAND's 13m diameter target volume provides a suitable environment to measure energy and position dependence of the detected neutrino flux. A characteristic oscillation pattern would be visible for a baseline of about 10 m or less, providing a very clean signal of neutrino disappearance into a yet-unknown, "sterile" state. Such a measurement will be free of any reactor-related uncertainties. After 1.5 years of data taking the Reactor Antineutrino Anomaly parameter space will be tested at > 95% C.L.
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