761 research outputs found
Symmetry Breaking for Matter Coupled to Linearized Supergravity From the Perspective of the Current Supermultiplet
We consider a generic supersymmetric matter theory coupled to linearized
supergravity, and analyze scenarios for spontaneous symmetry breaking in terms
of vacuum expectation values of components of the current supermultiplet. When
the vacuum expectation of the energy momentum tensor is zero, but the scalar
current or pseudoscalar current gets an expectation, evaluation of the
gravitino self energy using the supersymmetry current algebra shows that there
is an induced gravitino mass term. The structure of this term generalizes the
supergravity action with cosmological constant to theories with CP violation.
When the vacuum expectation of the energy momentum tensor is nonzero,
supersymmetry is broken; requiring cancellation of the cosmological constant
gives the corresponding generalized gravitino mass formula.Comment: 11 page
Motional Squashed States
We show that by using a feedback loop it is possible to reduce the
fluctuations in one quadrature of the vibrational degree of freedom of a
trapped ion below the quantum limit. The stationary state is not a proper
squeezed state, but rather a ``squashed'' state, since the uncertainty in the
orthogonal quadrature, which is larger than the standard quantum limit, is
unaffected by the feedback action.Comment: 8 pages, 2 figures, to appear in the special Issue "Quantum
Correlations and Fluctuations" of J. Opt.
Nonrenormalization of Flux Superpotentials in String Theory
Recent progress in understanding modulus stabilization in string theory
relies on the existence of a non-renormalization theorem for the 4D
compactifications of Type IIB supergravity which preserve N=1 supersymmetry. We
provide a simple proof of this non-renormalization theorem for a broad class of
Type IIB vacua using the known symmetries of these compactifications, thereby
putting them on a similar footing as the better-known non-renormalization
theorems of heterotic vacua without fluxes. The explicit dependence of the
tree-level flux superpotential on the dilaton field makes the proof more subtle
than in the absence of fluxes.Comment: 16 pages, no figures. Final version, to appear in JHEP. Arguments for
validity of R-symmetry made more explicit. Minor extra comments and
references adde
Comparison of shoot fly resistance qtls in sorghum introgression lines using snp genotyping
Shoot fly is a major pest in sorghum that causes significant annual yield loss. Use of pesticide to control this pest is an expensive and environmentally unsafe approach. Present study investigated the host plant resistance mechanism to develop shoot fly resistance (SFR) lines through transfer of shoot fly resistance QTLs (glossiness, trichome density, ovipositional non-preference) using SSR marker assisted backcrossing. Genomic regions for SFR showed four QTLs on SBI 01, SBI 07, SBI 05 and SBI 10 contributing up to 11.5%, 18.3%, 14% and 14.7% phenotypic variation. But QTLs on SBI 05 and SBI 10 for glossiness and trichome density are the major QTLs for which 10 SNPs have been designed. In earlier studies, three QTL regions associated with shoot fly resistance were successfully introgressed into elite cultivar SPV 1411 (Parbhani Moti) and a B line ICSB29004 using donors viz. J2658 (SBI01), J2614 (SBI10), and J2714
(SBI07) (which are derivatives of BTx 623). Phenotyping of introgression lines (ILs) led to the identification of resistant lines for each QTL region present on chromosome SBI-01, SBI-07 and SBI-10. Hence, in this study we have analysed the above developed ILs using single-nucleotide polymorphism (SNP) markers tightly linked to shoot fly resistant QTLs. The results showed that introgression lines with QTL present on chromosome SBI-10 were segregating for favorable alleles for leaf glossiness and for trichome density in homozygous condition. Other introgression lines with QTLs on chromosome SBI-01 and SBI-07 for component traits - oviposition non-preference, seedling vigor are segregated for glossiness trait also thus showing the transfer of non-targeted region, which in this case proved beneficial for SFR. This study showed that these SNPs can be used to analyze introgression lines and can be used as genomic markers for early generation selection of shoot fly resistance lines
Data-based estimates of the ocean carbon sink variability â First results of the Surface Ocean pCO2 Mapping intercomparison (SOCOM)
Using measurements of the surface-ocean CO2 partial pressure (pCO2) and 14 different pCO2 mapping methods recently collated by the Surface Ocean pCO2 Mapping intercomparison (SOCOM) initiative, variations in regional and global seaâair CO2 fluxes are investigated. Though the available mapping methods use widely different approaches, we find relatively consistent estimates of regional pCO2 seasonality, in line with previous estimates. In terms of interannual variability (IAV), all mapping methods estimate the largest variations to occur in the eastern equatorial Pacific. Despite considerable spread in the detailed variations, mapping methods that fit the data more closely also tend to agree more closely with each other in regional averages. Encouragingly, this includes mapping methods belonging to complementary types â taking variability either directly from the pCO2 data or indirectly from driver data via regression. From a weighted ensemble average, we find an IAV amplitude of the global seaâair CO2 flux of 0.31 PgC yrâ1 (standard deviation over 1992â2009), which is larger than simulated by biogeochemical process models. From a decadal perspective, the global ocean CO2 uptake is estimated to have gradually increased since about 2000, with little decadal change prior to that. The weighted mean net global ocean CO2 sink estimated by the SOCOM ensemble is â1.75 PgC yrâ1 (1992â2009), consistent within uncertainties with estimates from ocean-interior carbon data or atmospheric oxygen trend
Gravitino Dark Matter Scenarios with Massive Metastable Charged Sparticles at the LHC
We investigate the measurement of supersymmetric particle masses at the LHC
in gravitino dark matter (GDM) scenarios where the next-to-lightest
supersymmetric partner (NLSP) is the lighter scalar tau, or stau, and is stable
on the scale of a detector. Such a massive metastable charged sparticle would
have distinctive Time-of-Flight (ToF) and energy-loss () signatures. We
summarise the documented accuracies expected to be achievable with the ATLAS
detector in measurements of the stau mass and its momentum at the LHC. We then
use a fast simulation of an LHC detector to demonstrate techniques for
reconstructing the cascade decays of supersymmetric particles in GDM scenarios,
using a parameterisation of the detector response to staus, taus and jets based
on full simulation results. Supersymmetric pair-production events are selected
with high redundancy and efficiency, and many valuable measurements can be made
starting from stau tracks in the detector. We recalibrate the momenta of taus
using transverse-momentum balance, and use kinematic cuts to select
combinations of staus, taus, jets and leptons that exhibit peaks in invariant
masses that correspond to various heavier sparticle species, with errors often
comparable with the jet energy scale uncertainty.Comment: 23 pages, 10 figures, updated to version published in JHE
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