This paper considers unitarity and CPT constraints on asymmetric freeze-in, the use of freeze-in to store baryon number in a dark sector. In this scenario, Sakharov's out of equilibrium condition is satisfied by placing the visible and hidden sectors at different temperatures while a net visible baryon number is produced by storing negative baryon number in a dark sector. It is shown that unitarity and CPT lead to unexpected cancellations. In particular, the transfer of baryon number cancels completely at leading order. This note has shown that if two sectors are in thermal equilibrium with themselves, but not with each other, then the leading effect transferring conserved quantities between the two sectors is of order the the weak coupling connecting them to the third power. When freeze-in is used to produce a net baryon number density, the leading order effect comes from {Omicron}({lambda}{sup 3}) diagrams where the intermediate state that goes on-shell has a different visible baryon number than the final state visible baryon number. Models in which the correct baryon number is generated with freeze-in as the dominant source of abundance, typically require {lambda} {approx}> 10{sup -6} and m{sub bath} {approx}> TeV. m{sub bath} is the mass of the …

Ionic crystals terminated at oppositely charged polar surfaces are inherently unstable and expected to undergo surface reconstructions to maintain electrostatic stability. Essentially, an electric field that arises between oppositely charged atomic planes gives rise to a built-in potential that diverges with thickness. Here we present evidence of such a built-in potential across polar LaAlO{sub 3} thin films grown on SrTiO{sub 3} substrates, a system well known for the electron gas that forms at the interface. By performing tunneling measurements between the electron gas and metallic electrodes on LaAlO{sub 3} we measure a built-in electric field across LaAlO{sub 3} of 80.1 meV/{angstrom}. Additionally, capacitance measurements reveal the presence of an induced dipole moment across the heterostructure. We forsee use of the ionic built-in potential as an additional tuning parameter in both existing and novel device architectures, especially as atomic control of oxide interfaces gains widespread momentum.

Although the parent iron-based pnictides and chalcogenides are itinerant antiferromagnets, the use of local moment picture to understand their magnetic properties is still widespread. We study magnetic Raman scattering from a local moment perspective for various quantum spin models proposed for this new class of superconductors. These models vary greatly in the level of magnetic frustration and show a vastly different two-magnon Raman response. Light scattering by two-magnon excitations thus provides a robust and independent measure of the underlying spin interactions. In accord with other recent experiments, our results indicate that the amount of magnetic frustration in these systems may be small.

Two new criticality modeling approaches have greatly increased the efficiency of dissolver operations in H-Canyon. The first new approach takes credit for the linear, physical distribution of the mass throughout the entire length of the fuel assembly. This distribution of mass is referred to as the linear density. Crediting the linear density of the fuel bundles results in using lower fissile concentrations, which allows higher masses to be charged to the dissolver. Also, this approach takes credit for the fact that only part of the fissile mass is wetted at a time. There are multiple assemblies stacked on top of each other in a bundle. On average, only 50-75% of the mass (the bottom two or three assemblies) is wetted at a time. This means that only 50-75% (depending on operating level) of the mass is moderated and is contributing to the reactivity of the system. The second new approach takes credit for the progression of the dissolving process. Previously, dissolving analysis looked at a snapshot in time where the same fissile material existed both in the wells and in the bulk solution at the same time. The second new approach models multiple consecutive phases that simulate the fissile material …

We examine the scenario where a leptophobic Z{prime} boson accounts for the excess of events in the Wjj channel as observed by CDF. We assume generation independent couplings for the Z{prime} and obtain allowed regions for the four hadronic couplings using the measured cross section as well as constraints from dijet production at UA2. These coupling regions translate into well-determined rates for the associated production of Z/{gamma} + Z{prime} at the Tevatron and LHC, as well as W + Z{prime} at the LHC,that are directly correlated with the Wjj rate observed at the Tevatron. The Wjj rate at the LHC is large and this channel should be observed soon once the SM backgrounds are under control. The rates for Z/{gamma} + Z{prime} associated production are smaller, and these processes should not yet have been observed at the Tevatron given the expected SM backgrounds. In addition, we show that more coupling information is obtainable from the M{sub WZ{prime}} distribution. Once detected, these processes will provide further valuable information on the Z{prime} boson couplings.

We analyze the phase structure of supersymmetric chiral gauge theories with gauge group SU(N), an antisymmetric, and F {le} N + 3 flavors, in the presence of a cubic superpotential. When F = N + 3 the theory flows to a superconformal fixed point in the infrared, and new dual descriptions of this theory are uncovered. The theory with odd N admits a self-dual magnetic description. For general N, we find an infinite family of magnetic dual descriptions, characterized by arbitrarily large gauge groups and additional classical global symmetries that are truncated by nonperturbative effects. The infrared dynamics of these theories are analyzed using a-maximization, which supports the claim that all these theories flow to the same superconformal fixed point. A very rich phase structure is found when the number of flavors is reduced below N + 3, including a new self-dual point, transitions from conformal to confining, and a nonperturbative instability for F {le} N. We also give examples of chiral theories with antisymmetrics that have nonchiral duals.

Controlling electric loads to deliver power system services presents a number of interesting challenges. For example, changes in electricity consumption of Commercial and Industrial (C&I) facilities are usually estimated using counterfactual baseline models, and model uncertainty makes it difficult to precisely quantify control responsiveness. Moreover, C&I facilities exhibit variability in their response. This paper seeks to understand baseline model error and demand-side variability in responses to open-loop control signals (i.e. dynamic prices). Using a regression-based baseline model, we define several Demand Response (DR) parameters, which characterize changes in electricity use on DR days, and then present a method for computing the error associated with DR parameter estimates. In addition to analyzing the magnitude of DR parameter error, we develop a metric to determine how much observed DR parameter variability is attributable to real event-to-event variability versus simply baseline model error. Using data from 38 C&I facilities that participated in an automated DR program in California, we find that DR parameter errors are large. For most facilities, observed DR parameter variability is likely explained by baseline model error, not real DR parameter variability; however, a number of facilities exhibit real DR parameter variability. In some cases, the aggregate population of C&I …

We present a study of the experimental determination of the forward-backward asymmetry in the process e{sup +}e{sup -} {yields} t{bar t} and in the subsequent t {yields} Wb decay, studied in the context of the International Linear Collider. This process probes the elementary couplings of the top quark to the photon, the Z and the W bosons at a level of precision that is difficult to achieve at hadron colliders. Measurement of the forward-backward asymmetry requires excellent b quark identification and determination of the quark charge. The study reported here is performed in the most challenging all-hadronic channel e{sup +}e{sup -} {yields} b{bar b}q{bar q}q{bar q}. It includes realistic details of the experimental environment, a full Monte Carlo simulation of the detector, based on the Silicon Detector concept, and realistic event reconstruction. The forward-backward asymmetries are determined to a precision of approximately 1% for each of two choices of beam polarization. We analyze the implications for the determination of the t{bar t}Z and Wt{bar b} couplings.

This work explores the potential reach of the 7 TeV LHC to new colored states in the context of simplified models and addresses the issue of which search regions are necessary to cover an extensive set of event topologies and kinematic regimes. This article demonstrates that if searches are designed to focus on specific regions of phase space, then new physics may be missed if it lies in unexpected corners. Simple multiregion search strategies can be designed to cover all of kinematic possibilities. A set of benchmark models are created that cover the qualitatively different signatures and a benchmark multiregion search strategy is presented that covers these models.

We present searches for rare or forbidden charm decays of the form X{sub c}{sup +} {yields} h{sup {+-}}{ell}{sup {-+}}{ell}{sup ({prime})+}, where X{sub c}{sup +} is a charm hardron (D{sup +}, D{sub s}{sup +}, or {Lambda}{sub c}{sup +}), h{sup {+-}} is a pion, kaon, or proton, and {ell}{sup ({prime}){+-}} is an electron or muon. The analysis is based on 384 fb{sup -1} of e{sup +}e{sup -} annihilation data collected at or close to the {Upsilon}(4S) resonance with the BABAR detector at the SLAC National Accelerator Laboratory. No significant signal is observed for any of the 35 decay modes that are investigated. We establish 90% confidence-level upper limits on the branching fractions between 1 x 10{sup -6} and 44 x 10{sup -6} depending on the channel. In most cases, these results represent either the first limits or significant improvements on existing limits for the decay modes studied.

We present an infinite class of 2+1 dimensional field theories which, after coupling to semi-holographic fermions, exhibit strange metallic behavior in a suitable large N limit. These theories describe lattices of hypermultiplet defects interacting with parity-preserving supersymmetric Chern-Simons theories with U(N) x U(N) gauge groups at levels {+-}k. They have dual gravitational descriptions in terms of lattices of probe M2 branes in AdS{sub 4} x S{sup 7}/Z{sub k} (for N >> 1,N >> k{sup 5}) or probe D2 branes in AdS{sub 4} x CP{sup 3} (for N >> k >> 1,N << k{sup 5}). We discuss several challenges one faces in maintaining the success of these models at finite N, including backreaction of the probes in the gravity solutions and radiative corrections in the weakly coupled field theory limit.

The ({pi},{pi}) shadow band (SB) in La-based cuprate family (La214) was studied by angle-resolved photoemission spectroscopy (ARPES) over a wide doping range from x = 0.01 to x = 0.25. Unlike the well-studied case of the Bi-based cuprate family, an overall strong, monotonic doping dependence of the SB intensity at the Fermi level (E{sub F}) was observed. In contrast to a previous report for the presence of the SB only close to x = 1/8, we found it exists in a wide doping range, associated with a doping-independent ({pi},{pi}) wave vector but strongly doping-dependent intensity: It is the strongest at x {approx} 0.03 and systematically diminishes as the doping increases until it becomes negligible in the overdoped regime. This SB with the observed doping dependence of intensity can in principle be caused by the antiferromagnetic fluctuations or a particular form of low-temperature orthorhombic lattice distortion known to persist up to x {approx} 0.21 in the system, with both being weakened with increasing doping. However, a detailed binding energy dependent analysis of the SB at x = 0.07 does not appear to support the former interpretation, leaving the latter as a more plausible candidate, despite a challenge in quantitatively linking the …

A method is introduced for diagnosing a transilient matrix for moist convection. This transilient matrix quantifies the nonlocal transport of air by convective eddies: for every height z, it gives the distribution of starting heights z{prime} for the eddies that arrive at z. In a cloud-resolving simulation of deep convection, the transilient matrix shows that two-thirds of the subcloud air convecting into the free troposphere originates from within 100 m of the surface. This finding clarifies which initial height to use when calculating convective available potential energy from soundings of the tropical troposphere.

Globally, soil organic matter (SOM) contains more than three times as much carbon as either the atmosphere or terrestrial vegetation. Yet it remains largely unknown why some SOM persists for millennia whereas other SOM decomposes readily—and this limits our ability to predict how soils will respond to climate change. Recent analytical and experimental advances have demonstrated that molecular structure alone does not control SOM stability: in fact, environmental and biological controls predominate. Here we propose ways to include this understanding in a new generation of experiments and soil carbon models, thereby improving predictions of the SOM response to global warming.

The attractor mechanism governs the near-horizon geometry of extremal black holes in ungauged 4D N=2 supergravity theories and in Calabi-Yau compactifications of string theory. In this paper, we study a natural generalization of this mechanism to solutions of arbitrary 4D N=2 gauged supergravities. We define generalized attractor points as solutions of an ansatz which reduces the Einstein, gauge field, and scalar equations of motion to algebraic equations. The simplest generalized attractor geometries are characterized by non-vanishing constant anholonomy coefficients in an orthonormal frame. Basic examples include Lifshitz and Schroedinger solutions, as well as AdS and dS vacua. There is a generalized attractor potential whose critical points are the attractor points, and its extremization explains the algebraic nature of the equations governing both supersymmetric and non-supersymmetric attractors.

At the LHC, top quark pairs are dominantly produced from gluons, making it difficult to measure the top quark forward-backward asymmetry. To improve the asymmetry measurement, we study variables that can distinguish between top quarks produced from quarks and those from gluons: the invariant mass of the top pair, the rapidity of the top-antitop system in the lab frame, the rapidity of the top quark in the top-antitop rest frame, the top quark polarization and the top-antitop spin correlation. We combine all the variables in a likelihood discriminant method to separate quark-initiated events from gluon-initiated events. We apply our method on models including G-prime's and W-prime's motivated by the recent observation of a large top quark forward-backward asymmetry at the Tevatron. We have found that the significance of the asymmetry measurement can be improved by 10% to 30%. At the same time, the central values of the asymmetry increase by 40% to 100%. We have also analytically derived the best spin quantization axes for studying top quark polarization as well as spin-correlation for the new physics models.

Electric field penetration into the metallic side of a Schottky junction is in principle a universal phenomenon, the magnitude of which increases with the semiconductor permittivity. Here, we quantitatively probe this effect using bias-dependent internal photoemission spectroscopy at the Schottky junction between a large dielectric permittivity semiconductor SrTiO{sub 3} and gold. A clear linear reduction of the barrier height with increasing interface electric field was observed, highlighting the importance of field penetration into the gold. The interfacial permittivity of SrTiO{sub 3} at the interface is reduced from the bulk value, reflecting intrinsic suppression at the interface.

The generalization of the MSSM to the case of four chiral fermion generations (4GMSSM) can lead to significant changes in the phenomenology of the otherwise familiar Higgs sector. In most of the 3GMSSM parameter space, the lighter CP-even h is {approx} 115-125 GeV and mostly Standard Model-like while H,A,H{sup {+-}} are all relatively heavy. Furthermore, the ratio of Higgs vevs, tan {beta}, is relatively unconstrained. In contrast to this, in the 4GMSSM, heavy fourth generation fermion loops drive the masses of h,H,H{sup {+-}} to large values while the CP-odd boson, A, can remain relatively light and tan {beta} is restricted to the range 1/2 {approx}< tan {beta} {approx}< 2 due to perturbativity requirements on Yukawa couplings. We explore this scenario in some detail, concentrating on the collider signatures of the light CP-odd Higgs at both the Tevatron and LHC. We find that while gg {yields} A may lead to a potential signal in the {tau}{sup +}{tau}{sup -} channel at the LHC, A may first be observed in the {gamma}{gamma} channel due to a highly loop-enhanced cross section that can be more than an order of magnitude greater than that of a SM Higgs for A masses of {approx} 115-120 and …

None

None

We present branching fraction and CP asymmetry measurements as well as angular studies of B {yields} {phi}{phi}K decays using 464 x 10{sup 6} B{bar B} events collected by the BABAR experiment. The branching fractions are measured in the {phi}{phi} invariant mass range below the {eta}{sub c} resonance (m{sub {phi}{phi}} < 2.85 GeV). We find {Beta}(B{sup +} {yields} {phi}{phi}K{sup +}) = (5.6 {+-} 0.5 {+-} 0.3) x 10{sup -6} and {Beta}(B{sup 0} {yields} {phi}{phi}K{sup 0}) = (4.5 {+-} 0.8 {+-} 0.3) x 10{sup -6}, where the first uncertaintiy is statistical and the second systematic. The measured direct CP asymmetries for the B{sup {+-}} decays are A{sub CP} = -0.10 {+-} 0.08 {+-} 0.02 below the {eta}{sub c} threshold (m{sub {phi}{phi}} < 2.85 GeV) and A{sub CP} = 0.09 {+-} 0.10 {+-} 0.02 in the {eta}{sub c} resonance region (m{sub {phi}{phi}} in [2.94,3.02] GeV). Angular distributions are consistent with J{sub P} = 0{sup -} in the {eta}{sub c} resonance region and favor J{sup P} = 0{sup +} below the {eta}{sub c} resonance.

The authors use (111 {+-} 1) million {Upsilon}(3S) and (89 {+-} 1) million {Upsilon}(2S) events recorded by the BABAR detector at the PEP-II B-factory at SLAC to perform a study of radiative transitions betwen bottomonium states using photons that have been converted to e{sup +}e{sup -} pairs by the detector material. They observe {Upsilon}(3S) {yields} {gamma}{chi}{sub b0,2}(1P) decay, make precise measurements of the branching fractions for {chi}{sub b1,2}(1P, 2P) {yields} {gamma}{Upsilon}(1S) and {chi}{sub b1,2}(2P) {yields} {gamma}{Upsilon}(2S) decays, and search for radiative decay to the {eta}{sub b}(1S) and {eta}{sub b}(2S) states.