5,189 research outputs found
The Design and Performance of the MINERvA Detector
The MINERvA experiment is designed to make precision measurements of various
neutrino cross sections in the low energy regime. We describe the detector and
give the performance of some of the measured quantities.Comment: 4 pages, 4 pages, 3 figures, DPF04 proceeding
Modeling Neutrino Quasielastic Cross Sections on Nucleons and Nuclei
We calculate the total and differential quasielastic cross sections for
neutrino and antineutrino scattering on nucleons using up to date fits to the
nucleon elastic electromagnetic form factors , , ,
, and and pseudoscalar form factors. We compare predictions of the
cross sections for nucelons and nuclei to experimental data.Comment: 5 pages, 4 figures, Presented by Arie Bodek at CIPANP2003, New York
City, NY 2003 - to be published in proceeding
Resolving the Axial Mass Anomaly in neutrino Scattering
We present a parametrization of the observed enhancement in the transverse
electron quasielastic (QE) response function for nucleons bound in carbon as a
function of the square of the four momentum transfer (Q2) in terms of a
correction to the magnetic form factors of bound nucleons. The parametrization
should also be applicable to the transverse cross section in neutrino
scattering. If the transverse enhancement originates from meson exchange
currents (MEC), then it is theoretically expected that any enhancement in the
longitudinal or axial contributions is small. We present the predictions of the
"Transverse Enhancement" model (which is based on electron scattering data
only) for the neutrino and anti-neutrino differential and total QE cross
sections for nucleons bound in carbon. The 2Q2 dependence of the transverse
enhancement is observed to resolve much of the long standing discrepancy
("Axial Mass Anomaly}) in the QE total cross sections and differential
distributions between low energy and high energy neutrino experiments on
nuclear targets.Comment: 3 pages, 3 Figures, Presented by Arie Bodek at the 19th Particles and
Nuclei International Conference, PANIC 2011, MIT, Cambridge, MA July 201
Vector and Axial Nucleon Form Factors:A Duality Constrained Parameterization
We present new parameterizations of vector and axial nucleon form factors. We
maintain an excellent descriptions of the form factors at low momentum
transfers, where the spatial structure of the nucleon is important, and use the
Nachtman scaling variable xi to relate elastic and inelastic form factors and
impose quark-hadron duality constraints at high momentum transfers where the
quark structure dominates. We use the new vector form factors to re-extract
updated values of the axial form factor from neutrino experiments on deuterium.
We obtain an updated world average value from neutrino-d and pion
electroproduction experiments of M_A = 1.014 +- 0.014 GeV/c2. Our
parameterizations are useful in modeling neutrino interactions at low energies
(e.g. for neutrino oscillations experiments). The predictions for high momentum
transfers can be tested in the next generation electron and neutrino scattering
experiments.Comment: 5 pages, 3 figures, to be published in EPJ
Fiber R and D for the CMS HCAL
This paper documents the fiber R and D for the CMS hadron barrel calorimeter
(HCAL). The R and D includes measurements of fiber flexibility, splicing,
mirror reflectivity, relative light yield, attenuation length, radiation
effects, absolute light yield, and transverse tile uniformity. Schematics of
the hardware for each measurement are shown. These studies are done for
different diameters and kinds of multiclad fiber.Comment: 23 pages, 30 Figures 89 pages, 41 figures, corresponding author: H.
Budd, [email protected]
Letter from James H. Budd to John Muir, 1895 Jan 9.
Sacramento, Jan. 9, 1895.John Muir, Esq.,President Sierra Club, Academy of Sciences Building,San Francisco, Cal.Dear Sir:Please accept my thanks for the copy of resolutions of the Sierra Club which you were kind enough to send me. Will look into the matter as soon as I possibly 8an.Yours sincerely,Illegible0191
Interplay of Mre11 Nuclease with Dna2 plus Sgs1 in Rad51-Dependent Recombinational Repair
The Mre11/Rad50/Xrs2 complex initiates IR repair by binding to the end of a double-strand break, resulting in 5′ to 3′ exonuclease degradation creating a single-stranded 3′ overhang competent for strand invasion into the unbroken chromosome. The nuclease(s) involved are not well understood. Mre11 encodes a nuclease, but it has 3′ to 5′, rather than 5′ to 3′ activity. Furthermore, mutations that inactivate only the nuclease activity of Mre11 but not its other repair functions, mre11-D56N and mre11-H125N, are resistant to IR. This suggests that another nuclease can catalyze 5′ to 3′ degradation. One candidate nuclease that has not been tested to date because it is encoded by an essential gene is the Dna2 helicase/nuclease. We recently reported the ability to suppress the lethality of a dna2Δ with a pif1Δ. The dna2Δ pif1Δ mutant is IR-resistant. We have determined that dna2Δ pif1Δ mre11-D56N and dna2Δ pif1Δ mre11-H125N strains are equally as sensitive to IR as mre11Δ strains, suggesting that in the absence of Dna2, Mre11 nuclease carries out repair. The dna2Δ pif1Δ mre11-D56N triple mutant is complemented by plasmids expressing Mre11, Dna2 or dna2K1080E, a mutant with defective helicase and functional nuclease, demonstrating that the nuclease of Dna2 compensates for the absence of Mre11 nuclease in IR repair, presumably in 5′ to 3′ degradation at DSB ends. We further show that sgs1Δ mre11-H125N, but not sgs1Δ, is very sensitive to IR, implicating the Sgs1 helicase in the Dna2-mediated pathway
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