The magnetized steel and scintillator calorimeters of the MINOS experiment

The Main Injector Neutrino Oscillation Search (MINOS) experiment uses an accelerator-produced neutrino beam to perform precision measurements of the neutrino oscillation parameters in the 'atmospheric neutrino' sector associated with muon neutrino disappearance. This long-baseline experiment measures neutrino interactions in Fermilab's NuMI neutrino beam with a near detector at Fermilab and again 735 km downstream with a far detector in the Soudan Underground Laboratory in northern Minnesota. The two detectors are magnetized steel-scintillator tracking calorimeters. They are designed to be as similar as possible in order to ensure that differences in detector response have minimal impact on the comparisons of event rates, energy spectra and topologies that are essential to MINOS measurements of oscillation parameters. The design, construction, calibration and performance of the far and near detectors are described in this paper

Pearl millet with higher stover yield and better forage quality: Identification of new germplasm and cultivars

Pearl millet is a source of both food grains for humans and dry fodder for their ruminant livestock in the semi-arid and arid tropics of Asia and Africa. Recently, pearl millet has occupied large areas during summer season in India and is also in great demand in central Asian countries for cultivation as forage crop, but very few cultivar options are available to farmers for this ecology. The objective of this study was to: 1) identify sources of higher stover yield and fodder quality traits, 2) initiate their utilization in breeding programs; and 3) identify OPVs and hybrids with higher stover yield and fodder quality. A set of 242 pearl millets from a minicore collection was evaluated for stover linked traits during summer and rainy seasons of 2013 at ICRISAT, Patancheru. Based on 2-season evaluation, about 10% best (21 accessions) having high fresh stover yield (23 to 38 tons ha-1) and dry stover yield (8 to 13 tons ha–1) at 85–90 days after planting were selected and further evaluated in the rainy season of 2014 along with checks at 6 locations in India. The dry stover yield of check OPVs varied from 15–21 tons ha–1, and in check hybrids from 16 tons (DFMH 30) to 19.7 tons ha–1 (Nutrifeed). IP 22269 had highest dry stover yield (19 tons ha–1), followed by IP 20577 (18 tons ha–1) and IP 20409 (16.6 tons ha–1) and total of 11 accessions had dry stover yield of >14 tons ha–1. These accessions were also evaluated at ICRISAT during rainy season of 2014 along with earlier identified OPVs/germplasm accessions and top-cross hybrids. The identified 21 accessions had a wide range of stover nitrogen content (0.88 to 1.24%), in vitro digestibility (39.8 to 45.4%), and metabolizable energy (ME) (5.3 to 6.4 MJ·kg–1). Twenty of these identified accessions had in vitro digestibility of >40 %; and IP 14294 had highest in vitro digestibility (45.4%) along with highest ME (6.4 MJ·kg–1). These identified accessions were subjected to inbreeding yielding about 270 early generation inbreds (S1s-S3s), which will further be used for deriving breeding lines for the development of new hybrids and OPVs with high stover yield and fodder quality. Also, based on 2-year (2013 and 2014) multilocation evaluation at 5 locations in each year for stover yield and at one location (ICRISAT) for stover quality traits, five OPVs/germplasm accessions having high stover yield in the range of 16.3 to 17.8 tons ha–1, and in vitro digestibility from 42 to 45%; and five top cross hybrids having dry stover yield of 13.6 to 15.9 tons ha–1, with in vitro digestibility from 38.9 to 42.6% were identified; though top cross hybrids matured about 10–15 days earlier than the OPVs

Baryon Operators and Baryon Spectroscopy

The issues involved in a determination of the baryon resonance spectrum in lattice QCD are discussed. The variational method is introduced and the need to construct a sufficient basis of interpolating operators is emphasised. The construction of baryon operators using group-theory techniques is outlined. We find that the use both of quark-field smearing and link-field smearing in the operators is essential firstly to reduce the coupling of operators to high-frequency modes and secondly to reduce the gauge-field fluctuations in correlators. We conclude with a status report of our current investigation of baryon spectroscopy.Comment: Invited talk at Workshop on Computational Hadron Physics, Cyprus, Sept. 14-17, 200

Multilayer broadband anti-reflective coatings for bulk heterojunction polymer solar cells

The photocurrent produced by solar cells is limited by reflection losses for all types of photovoltaic devices. The first reflection loss occurs at the glass/air interface of the photovoltaic device. A solar cell without a light trapping mechanism in place loses around 4 % of the solar energy at this interface. To minimise the losses, a broadband multilayer thin film anti-reflection (MAR) coating has been designed and deposited onto the glass surface of a solar cell. The coating consisted of four dielectric layers of alternating thin films of ZrO2 and SiO2. The layers were deposited by using high rate pulsed DC magnetron sputtering using time only for nanometre thickness control. Spectrophotometer measurements confirm that the transmission increased over the spectrum utilized by the bulk heterojunction (BHJ) solar cell (350nm- 700nm). The weighted average reflection reduced from 4.22% to 0.99%. BHJ solar cells with a PCDTBT:PCBM blend serving as the active layer were prepared on a MAR coated soda lime glass slides to verify the effectiveness of the coating. The efficiency increased by 0.18% at STC from 4.98% to 5.17% (a 3.7% relative increase). The gain was achieved by increasing the photocurrent from 11.96 mA/cm2 to 12.36 mA/cm2

Electron neutrino tagging through tertiary lepton detection

We discuss an experimental technique aimed at tagging electron neutrinos in multi-GeV artificial sources on an event-by-event basis. It exploits in a novel manner calorimetric and tracking technologies developed in the framework of the LHC experiments and of rare kaon decay searches. The setup is suited for slow-extraction, moderate power beams and it is based on an instrumented decay tunnel equipped with tagging units that intercept secondary and tertiary leptons from the bulk of undecayed \pi^+ and protons. We show that the taggers are able to reduce the \nue contamination originating from K_e3 decays by about one order of magnitude. Only a limited suppression (~60%) is achieved for \nue produced by the decay-in-flight of muons; for low beam powers, similar performance as for K_e3 can be reached supplementing the tagging system with an instrumented beam dump.Comment: 19 pages, 7 figures; minor changes, version to appear in EPJ

A_4 Symmetry and Lepton Masses and Mixing

Stimulated by Ma's idea which explains the tribimaximal neutrino mixing by assuming an A_4 flavor symmetry, a lepton mass matrix model is investigated. A Frogatt-Nielsen type model is assumed, and the flavor structures of the masses and mixing are caused by the VEVs of SU(2)_L-singlet scalars \phi_i^u and \phi_i^d (i=1,2,3), which are assigned to {\bf 3} and ({\bf 1}, {\bf 1}',{\bf 1}'') of A_4, respectively.Comment: 13 pages including 1 table, errors in Sec.7 correcte

Neutrino Quasielastic Scattering on Nuclear Targets: Parametrizing Transverse Enhancement (Meson Exchange Currents)

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 ($Q^2$) 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 $\nu_\mu, \bar{\nu}_\mu$ differential and total QE cross sections for nucleons bound in carbon. The $Q^2$ dependence of the transverse enhancement is observed to resolve much of the long standing discrepancy in the QE total cross sections and differential distributions between low energy and high energy neutrino experiments on nuclear targets.Comment: Revised Version- July 21, 2011: 17 pages, 20 Figures. To be published in Eur. Phys. J.

Cross-Correlation of the Cosmic Microwave Background with the 2MASS Galaxy Survey: Signatures of Dark Energy, Hot Gas, and Point Sources

We cross-correlate the Cosmic Microwave Background (CMB) temperature anisotropies observed by the Wilkinson Microwave Anisotropy Probe (WMAP) with the projected distribution of extended sources in the Two Micron All Sky Survey (2MASS). By modelling the theoretical expectation for this signal, we extract the signatures of dark energy (Integrated Sachs-Wolfe effect;ISW), hot gas (thermal Sunyaev-Zeldovich effect;thermal SZ), and microwave point sources in the cross-correlation. Our strongest signal is the thermal SZ, at the 3.1-3.7 \sigma level, which is consistent with the theoretical prediction based on observations of X-ray clusters. We also see the ISW signal at the 2.5 \sigma level, which is consistent with the expected value for the concordance LCDM cosmology, and is an independent signature of the presence of dark energy in the universe. Finally, we see the signature of microwave point sources at the 2.7 \sigma level.Comment: 35 pages (preprint format), 8 figures. In addition to minor revisions based on referee's comments, after correcting for a bug in the code, the SZ detection is consistent with the X-ray observations. Accepeted for publication in Physical Review