Physics

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Shiv Nadar University

Abstract: We propose a new mechanism to generate minuscule active neutrino masses in a five-dimensional (5d) spacetime of an interval without introducing SU(2)L singlet neutrinos. Under asymmetric boundary conditions on the two end points, a bulk mass for a 5d fermion allows a Dirac particle with a tiny mass eigenvalue. Implementing this mechanism, which provides us a new tool for building neutrino mass models, to the standard model gauge structure is possible when all the gauge bosons and the Higgs boson are localized on one of the branes. © 2016, The Author(s).

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(SoNS) School of Natural Sciences

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Journal of High Energy Physics

Active Dirac neutrinos via SU(2)L doublets in 5d

We consider lepton flavor violating Higgs decay, specifically h→μτ, in a leptoquark model. We introduce two scalar leptoquarks with the SU(3)c×SU(2)L×U(1)Y quantum numbers, (3,2,7/6) and (3,2,1/6), which do not generate dimension-4 operators mediating proton decay. They can mix with each other by interactions with the standard model Higgs. The constraint from the charged lepton flavor violating process, τ-→μ-γ, is very strong when only one leptoquark contribution is considered. However, we demonstrate that significant cancellation is possible between the two leptoquark contributions. We show that we can explain the CMS (ATLAS) excess in h→μτ. We also show that muon (g-2) anomaly can also be accommodated. © 2016 American Physical Society.

Physical Review D

Leptoquark explanation of h →μτ and muon (g-2)

The cholesterol partitioning and condensing effect in the liquid-ordered (Lo) and liquid-disordered (Ld) phases were systematically investigated for ternary mixture lipid multilayers consisting of 1:1 1,2-dipalmitoyl-sn-glycero-3-phosphocholine/1,2-dioleoyl-sn-glycero-3-phosphocholine with varying concentrations of cholesterol. X-ray lamellar diffraction was used to deduce the electron density profiles of each phase. The cholesterol concentration in each phase was quantified by fitting of the electron density profiles with a newly invented basic lipid profile scaling method that minimizes the number of fitting parameters. The obtained cholesterol concentration in each phase versus total cholesterol concentration in the sample increases linearly for both phases. The condensing effect of cholesterol in ternary lipid mixtures was evaluated in terms of phosphate-to-phosphate distances, which together with the estimated cholesterol concentration in each phase was converted into an average area per molecule. In addition, the cholesterol position was determined to a precision of (±0.7Å) and an increase of disorder in the lipid packing in the Lo phase was observed for total cholesterol concentration of 20∼30\%. © 2016 Biophysical Society.

Biophysical Journal

Cholesterol Partition and Condensing Effect in Phase-Separated Ternary Mixture Lipid Multilayers

Gel is an intermediate phase of solid and liquid, which exhibits properties of both, and this unique feature of gel has made it an excellent choice as a reaction medium for the nanomaterials synthesis. Herein, we report use of oil swollen surfactant gels as reaction medium and exfoliation medium, for the synthesis of metals (Au, Ag) nanoparticles and graphene, respectively. Confined growth of metals (Au and Ag) nanoparticles, has been achieved by exploring tween 80 based surfactant gel as a reaction medium. Au NPs prepared within tween 80 gel were found to be spherical with size ~5 nm, arranged in template micelles. Heating triggered the growth of Au nanoparticles and particles of various shapes including triangles, rods and pentagonal, were produced. Au and Ag containing tween 80 gels were found to be promising as catalysts for the nitrophenol reduction. Apart from separate synthesis of Au and Ag nanoparticles, bimetallic (Au-Ag) nanoparticles have also been synthesized by taking advantage of selective reducing property of tween 80. First time CTAB gel has been utilized as an exfoliation medium for the quick exfoliation of graphite into graphene sheets, eliminating the necessity of any external driving force such as sonication or heating, to reinforce exfoliation. © 2016 Elsevier Inc.

Journal of Colloid and Interface Science

Application of oil-swollen surfactant gels as a growth medium for metal nanoparticle synthesis, and as an exfoliation medium for preparation of graphene

<p>In this paper, a theoretical model is developed to investigate the performance of the hybrid solar thermoelectric generator (HSTEG) system, which is designed without (B-HSTEG) and with an evacuated glass tube (V-HSTEG). The heat loss, power output, thermal efficiency, and electrical efficiency of the B-HSTEG/V-HSTEG system are evaluated by analyzing the design parameters such as geometric solar concentration ratio, thermoelectric figure of merit, and cold-side inlet fluid temperature. The performance of the B-HSTEG is compared with the V-HSTEG system using two heat transfer fluids: water and Therminol VP-1. The maximum electrical efficiency of the B-HSTEG and V-HSTEG is estimated to be 12.2 and 15.6\% (ZT = 3) with a corresponding thermal efficiency of about 61.9 and 60.3\%, respectively. Overall, this paper provides a systematic performance analysis of HSTEG systems. © 2016 Taylor &amp; Francis Group, LLC.</p>

Energy Sources, Part A: Recovery, Utilization and Environmental Effects

Performance analysis of a hybrid solar thermoelectric generator

We calculate the k-point generating function of the correlated Jacobi ensemble using supersymmetric methods. We use the result for complex matrices for k=1 to derive a closed-form expression for the eigenvalue density. For real matrices we obtain the density in terms of a twofold integral that we evaluate numerically. For both expressions we find agreement when comparing with Monte Carlo simulations. Relations between these quantities for the Jacobi and the Cauchy–Lorentz ensemble are derived. © 2015, Springer Science+Business Media New York.

Journal of Statistical Physics

The Correlated Jacobi and the Correlated Cauchy–Lorentz Ensembles

Recently, deviations in flavor observables of B→D(∗)τν have been shown between the predictions in the Standard Model and the experimental results reported by BABAR, Belle, and LHCb collaborations. One of the solutions to this anomaly is obtained in a class of leptoquark model with a scalar leptoquark boson S1, which is a SU(3)c triplet and SU(2)L singlet particle with -1/3 hypercharge interacting with a quark-lepton pair. With well-adjusted couplings, this model can explain the anomaly and be compatible with all flavor constraints. In such a case, the S1 boson can be pair-produced at CERN's Large Hadron Collider (LHC) and subsequently decay as S1∗→tτ, bντ, and cτ. This paper explores the current 8 and 13 TeV constraints, as well as the detailed prospects at 14 TeV, of this flavor-motivated S1 model. From the current available 8 and 13 TeV LHC searches, we obtain constraints on the S1 boson mass for MS1<400-640 GeV depending on values of the leptoquark couplings to fermions. Then we study future prospects for this scenario at the 14 TeV LHC using detailed cut analyses and evaluate exclusion and discovery potentials for the flavor-motivated S1 leptoquark model from searches for the (bν)(bν) and (cτ)(cτ) final states. In the latter case, we consider several scenarios for the identification of charm jets. As a result, we find that the S1 leptoquark origin of the B→D(∗)τν anomaly can be probed with MS1600/800 GeV at the 14 TeV LHC with L=300/3000 fb-1 of accumulated data. One can also see that the 14 TeV LHC run II with L=300 fb-1 can exclude the S1 leptoquark boson up to MS1∼0.8 TeV at 95% confidence level, whereas a future 14 TeV LHC with L=3000 fb-1 data has a potential to discover the S1 leptoquark boson with its mass up to MS1∼1.1 TeV with over 5σ significance, from the (bν)(bν) and/or (cτ)(cτ) searches. © 2016 American Physical Society.

LHC constraints and prospects for S1 scalar leptoquark explaining the B →d (∗)τ ν anomaly LHC CONSTRAINTS and PROSPECTS for S1 ... DUMONT, NISHIWAKI, and WATANABE

We report the thermodynamic properties, magnetic ground state and microscopic magnetic model of the spin-1 frustrated antiferromagnet Li2NiW2O8, showing successive transitions at TN1≃18 K and TN2≃12.5 K in zero field. Nuclear magnetic resonance and neutron diffraction reveal collinear and commensurate magnetic order with the propagation vector k=(12,0,12) below TN2. The ordered moment of 1.8$\mu$B at 1.5 K is directed along [0.89(9),-0.10(5),-0.49(6)] and matches the magnetic easy axis of spin-1Ni2+ ions, which is determined by the scissor-like distortion of the NiO6 octahedra. Incommensurate magnetic order, presumably of spin-density-wave type, is observed in the region between TN2 and TN1. Density-functional band-structure calculations put forward a three-dimensional spin lattice with spin-1 chains running along the [011] direction and stacked on a spatially anisotropic triangular lattice in the ab plane. We show that the collinear magnetic order in Li2NiW2O8 is incompatible with the triangular lattice geometry and thus driven by a pronounced easy-axis single-ion anisotropy of Ni2+.

Physical Review B

Commensurate and incommensurate magnetic order in spin-1 chains stacked on the triangular lattice in Li2NiW2 O8

Abstract: Search for the bottom squarks (sbottoms) at the Large Hadron Collider (LHC) has recently assumed a heightened focus in the hunt for Supersymmetry (SUSY). The popular framework of the Next-to-Minimal Supersymmetric Standard Model (NMSSM) could conceive a naturally light sbottom which can easily be consistent with available constraints from the experiments at the LHC. Phenomenology of such sbottoms could in principle be as striking as that for a light top squark (stop) thanks to a rather nontrivial neutralino sector (with appreciable mixing among the neutral higgsinos and the singlino) that the scenario gives rise to. Nonetheless, finding such sbottoms would require a moderately large volume of data (∼300 fb−1) at the 13 TeV run of the LHC. A multi-channel analysis establishing a generic depletion of events in the usual 2b-jets + [InlineMediaObject not available: see fulltext.]T final state while registering, in conjunction, characteristically significant rates in various multi-lepton final states accompanied by b-jets might point not only to the presence of light sbottom(s) but could also shed crucial light on their compositions and the (singlino) nature of the lightest SUSY particle (LSP).

Sbottoms of natural NMSSM at the LHC

Ternary lipid mixtures incorporating cholesterol are well-known to phase separate into liquid-ordered (Lo) and liquid-disordered (Ld) phases. In multilayers of these systems, the laterally phase separated domains register in columnar structures with different bilayer periodicities, resulting in hydrophobic mismatch energies at the domain boundaries. In this paper, we demonstrate via synchrotron-based X-ray diffraction measurements that the system relieves the hydrophobic mismatch at the domain boundaries by absorbing larger amounts of inter-bilayer water into the Ld phase with lower d-spacing as the relative humidity approaches 100\%. The lamellar repeat distance of the Ld phase swells by an extra 4 Å, well beyond the equilibrium spacing predicted by the inter-bilayer forces. This anomalous swelling is caused by the hydrophobic mismatch energy at the domain boundaries, which produces a surprisingly long-range effect. We also demonstrate that the d-spacings of the lipid multilayers at 100\% relative humidity do not change when bulk water begins to condense on the sample. © the Owner Societies 2016.