1,397 research outputs found
Jets in Effective Theory: Summing Phase Space Logs
We demonstrate how to resum phase space logarithms in the Sterman-Weinberg
(SW) dijet decay rate within the context of Soft Collinear Effective theory
(SCET). An operator basis corresponding to two and three jet events is defined
in SCET and renormalized. We obtain the RGE of the two and three jet operators
and run the operators from the scale to the phase space scale . This phase space scale, where is the
cone half angle of the jet, defines the angular region of the jet. At we determine the mixing of the three and two jet operators. We
combine these results with the running of the two jet shape function, which we
run down to an energy cut scale . This defines the resumed SW
dijet decay rate in the context of SCET. The approach outlined here
demonstrates how to establish a jet definition in the context of SCET. This
allows a program of systematically improving the theoretical precision of jet
phenomenology to be carried out.Comment: 25 pages, 4 figures, V2: Typos fixed, writing clarified, detail on
PSRG added. Matching onto jet definition changed to taking place at collinear
scal
Application of the Frobenius method to the Schrodinger equation for a spherically symmetric potential: anharmonic oscillator
The power series method has been adapted to compute the spectrum of the
Schrodinger equation for central potential of the form . The bound-state energies
are given as zeros of a calculable function, if the potential is confined in a
spherical box. For an unconfined potential the interval bounding the energy
eigenvalues can be determined in a similar way with an arbitrarily chosen
precision. The very accurate results for various spherically symmetric
anharmonic potentials are presented.Comment: 16 pages, 5 figures, published in J. Phys
Nanosecond Optical Transmission Studies Of Laser Annealing In Ion-implanted Silicon-on-sapphire
Time-resolved optical transmission has been studied using 633 and 514 nm CW probes on ion-implantation-amorphized silicon-on-sapphire during annealing by a 10 nsec, ⊥ J/cm2 pulse at either 532 nm or 485 nm. As recrystallization sets in the transmitted signal at 514 nm rises by ⊥ 103 in ⊥ 60 nsec and provides a measure of regrowth velocity. Beyond 200 nsec the much slower transmission rise is used to provide an estimate of the Si cooling rate. The difference in transmission observed between initially crystalline and initially amorphous Si provide an estimate of the latent heat of recrystallization of the amorphous phase. © 1983
The Initial Mass Function in disc galaxies and in galaxy clusters: the chemo-photometric picture
The observed brightness of the Tully-Fisher relation suggests a low stellar
M/L ratio and a "bottom-light" IMF in disc galaxies, but the corresponding
efficiency of chemical enrichment tends to exceed the observational estimates.
Either suitable tuning of the IMF slope and mass limits or metal outflows from
disc galaxies must then be invoked.
A standard Solar Neighbourhood IMF cannot explain the high metallicity of the
hot intra-cluster medium: a different IMF must be at work in clusters of
galaxies. Alternatively, if the IMF is universal and chemical enrichment is
everywhere as efficient as observed in clusters, substantial loss of metals
must occur from the Solar Neighbourhood and from disc galaxies in general; a
"non-standard" scenario challenging our understanding of disc galaxy formation.Comment: 6 pages, 4 figures; in Proceedings of IMF@50: the Initial Mass
Function 50 years later; Corbelli, Palla and Zinnecker (eds.
Off-Critical Logarithmic Minimal Models
We consider the integrable minimal models , corresponding
to the perturbation off-criticality, in the {\it logarithmic
limit\,} , where are coprime and the
limit is taken through coprime values of . We view these off-critical
minimal models as the continuum scaling limit of the
Forrester-Baxter Restricted Solid-On-Solid (RSOS) models on the square lattice.
Applying Corner Transfer Matrices to the Forrester-Baxter RSOS models in Regime
III, we argue that taking first the thermodynamic limit and second the {\it
logarithmic limit\,} yields off-critical logarithmic minimal models corresponding to the perturbation of the critical
logarithmic minimal models . Specifically, in accord with the
Kyoto correspondence principle, we show that the logarithmic limit of the
one-dimensional configurational sums yields finitized quasi-rational characters
of the Kac representations of the critical logarithmic minimal models . We also calculate the logarithmic limit of certain off-critical
observables related to One Point Functions and show that the
associated critical exponents
produce all conformal dimensions in the infinitely extended Kac table. The corresponding Kac labels
satisfy . The exponent is obtained from the logarithmic limit of the free energy giving the
conformal dimension for the perturbing field . As befits a non-unitary
theory, some observables diverge at criticality.Comment: 18 pages, 5 figures; version 3 contains amplifications and minor
typographical correction
Virtual screening for inhibitors of the human TSLP:TSLPR interaction
The pro-inflammatory cytokine thymic stromal lymphopoietin (TSLP) plays a pivotal role in the pathophysiology of various allergy disorders that are mediated by type 2 helper T cell (Th2) responses, such as asthma and atopic dermatitis. TSLP forms a ternary complex with the TSLP receptor (TSLPR) and the interleukin-7-receptor subunit alpha (IL-7Ra), thereby activating a signaling cascade that culminates in the release of pro-inflammatory mediators. In this study, we conducted an in silico characterization of the TSLP: TSLPR complex to investigate the drugability of this complex. Two commercially available fragment libraries were screened computationally for possible inhibitors and a selection of fragments was subsequently tested in vitro. The screening setup consisted of two orthogonal assays measuring TSLP binding to TSLPR: a BLI-based assay and a biochemical assay based on a TSLP: alkaline phosphatase fusion protein. Four fragments pertaining to diverse chemical classes were identified to reduce TSLP: TSLPR complex formation to less than 75% in millimolar concentrations. We have used unbiased molecular dynamics simulations to develop a Markov state model that characterized the binding pathway of the most interesting compound. This work provides a proof-ofprinciple for use of fragments in the inhibition of TSLP: TSLPR complexation
EWPD Constraints on Flavor Symmetric Vector Fields
Electroweak precision data constraints on flavor symmetric vector fields are
determined. The flavor multiplets of spin one that we examine are the complete
set of fields that couple to quark bi-linears at tree level while not initially
breaking the quark global flavor symmetry group. Flavor safe vector masses
proximate to, and in some cases below, the electroweak symmetry breaking scale
are found to be allowed. Many of these fields provide a flavor safe mechanism
to explain the t tbar forward backward anomaly, and can simultaneously
significantly raise the allowed values of the Standard Model Higgs mass
consistent with electroweak precision data.Comment: Matches version published in JHE
Diabetes and Co-morbid Depression Among Racially Diverse, Low-Income Adults
Background
Research suggests individuals with diabetes are twice as likely as those without diabetes to be clinically depressed. Still unknown is the relationship between diabetes and depression in socioeconomically disadvantaged populations. Purpose
We examined the relationship between diabetes and depressive symptoms in a large, racially diverse, low-income cohort in the southeastern USA. Methods
A total of 69,068 adults were recruited from community health centers in 12 southeastern states. A fully adjusted polytomous logistic regression model tested the relationship between demographics, lifestyle behaviors, antidepressant use, body mass index, diabetes diagnosis, diabetes duration, diabetes medication compliance, and depressive symptoms using the Centers for Epidemiological Studies Depression scale. Results
Diabetes was present in 21.7% of sample. While a diabetes diagnosis was associated with having severe depressive symptoms (AOR, 1.24; 95% CI, 1.14–1.34), demographics, lifestyle behaviors, body mass index and antidepressant use were more strongly associated with severe depressive symptoms than a diabetes diagnosis. Conclusions
Having diabetes was associated with the presence and severity of depressive symptoms in a large, low-income sample of racially diverse adults. However, the relationship between diabetes and depressive symptoms was weaker than in other studies with higher socioeconomic groups
Probing for Invisible Higgs Decays with Global Fits
We demonstrate by performing a global fit on Higgs signal strength data that
large invisible branching ratios Br_{inv} for a Standard Model (SM) Higgs
particle are currently consistent with the experimental hints of a scalar
resonance at the mass scale m_h ~ 124 GeV. For this mass scale, we find
Br_{inv} < 0.64 (95 % CL) from a global fit to individual channel signal
strengths supplied by ATLAS, CMS and the Tevatron collaborations. Novel tests
that can be used to improve the prospects of experimentally discovering the
existence of a Br_{inv} with future data are proposed. These tests are based on
the combination of all visible channel Higgs signal strengths, and allow us to
examine the required reduction in experimental and theoretical errors in this
data that would allow a more significantly bounded invisible branching ratio to
be experimentally supported. We examine in some detail how our conclusions and
method are affected when a scalar resonance at this mass scale has couplings
deviating from the SM ones.Comment: 32pp, 15 figures v2: JHEP version, ref added & comment added after
Eq.
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