1,189 research outputs found
Relativistic Green's function approach to parity-violating quasielastic electron scattering
A relativistic Green's function approach to parity-violating quasielastic
electron scattering is presented. The components of the hadron tensor are
expressed in terms of the single particle Green's function, which is expanded
in terms of the eigenfunctions of the non-Hermitian optical potential, in order
to account for final state interactions without any loss of flux. Results for
C, O, and Ca are presented and discussed. The effect of
the strange quark contribution to the nuclear current is investigated.Comment: 24 pages, 13 figure
Anomalous Couplings in Double Higgs Production
The process of gluon-initiated double Higgs production is sensitive to
non-linear interactions of the Higgs boson. In the context of the Standard
Model, studies of this process focused on the extraction of the Higgs trilinear
coupling. In a general parametrization of New Physics effects, however, an even
more interesting interaction that can be tested through this channel is the
(ttbar hh) coupling. This interaction vanishes in the Standard Model and is a
genuine signature of theories in which the Higgs boson emerges from a
strongly-interacting sector. In this paper we perform a model-independent
estimate of the LHC potential to detect anomalous Higgs couplings in
gluon-fusion double Higgs production. We find that while the sensitivity to the
trilinear is poor, the perspectives of measuring the new (ttbar hh) coupling
are rather promising.Comment: 22 pages, 9 figures. v2: plots of Figs.8 and 9 redone to include
experimental uncertainty on the Higgs couplings, references adde
High EMSY expression defines a BRCA‐like subgroup of high‐grade serous ovarian carcinoma with prolonged survival and hypersensitivity to platinum
Background
Approximately half of high‐grade serous ovarian carcinomas (HGSOCs) demonstrate homologous recombination repair (HR) pathway defects, resulting in a distinct clinical phenotype comprising hypersensitivity to platinum, superior clinical outcome, and greater sensitivity to poly(adenosine diphosphate‐ribose) polymerase (PARP) inhibitors. EMSY, which is known to be amplified in breast and ovarian cancers, encodes a protein reported to bind and inactivate BRCA2. Thus, EMSY overexpression may mimic BRCA2 mutation, resulting in HR deficiency. However, to our knowledge, the phenotypic consequences of EMSY overexpression in HGSOC patients has not been explored.
Methods
Here we investigate the impact of EMSY expression on clinical outcome and sensitivity to platinum‐based chemotherapy using available data from transcriptomically characterized HGSOC cohorts.
Results
High EMSY expression was associated with better clinical outcome in a cohort of 265 patients with HGSOC from Edinburgh (overall survival multivariable hazard ratio, 0.58 [95% CI, 0.38‐0.88; P = .011] and progression‐free survival multivariable hazard ratio, 0.62 [95% CI, 0.40‐0.96; P = .030]). Superior outcome also was demonstrated in the Medical Research Council ICON7 clinical trial and multiple publicly available data sets. Patients within the Edinburgh cohort who had high EMSY expression were found to demonstrate greater rates of complete response to multiple platinum‐containing chemotherapy regimens (radiological complete response rate of 44.4% vs 12.5% at second exposure; P = .035) and corresponding prolonged time to disease progression (median, 151.5 days vs 60.5 days after third platinum exposure; P = .004).
Conclusions
Patients with HGSOCs demonstrating high EMSY expression appear to experience prolonged survival and greater platinum sensitivity, reminiscent of BRCA‐mutant cases. These data are consistent with the notion that EMSY overexpression may render HGSOCs HR deficient
Cooling of Dark-Matter Admixed Neutron Stars with density-dependent Equation of State
We propose a dark-matter (DM) admixed density-dependent equation of state
where the fermionic DM interacts with the nucleons via Higgs portal. Presence
of DM can hardly influence the particle distribution inside neutron star (NS)
but can significantly affect the structure as well as equation of state (EOS)
of NS. Introduction of DM inside NS softens the equation of state. We explored
the effect of variation of DM mass and DM Fermi momentum on the NS EOS.
Moreover, DM-Higgs coupling is constrained using dark matter direct detection
experiments. Then, we studied cooling of normal NSs using APR and DD2 EOSs and
DM admixed NSs using dark-matter modified DD2 with varying DM mass and Fermi
momentum. We have done our analysis by considering different NS masses. Also DM
mass and DM Fermi momentum are varied for fixed NS mass and DM-Higgs coupling.
We calculated the variations of luminosity and temperature of NS with time for
all EOSs considered in our work and then compared our calculations with the
observed astronomical cooling data of pulsars namely Cas A, RX J0822-43, 1E
1207-52, RX J0002+62, XMMU J17328, PSR B1706-44, Vela, PSR B2334+61, PSR
B0656+14, Geminga, PSR B1055-52 and RX J0720.4-3125. It is found that APR EOS
agrees well with the pulsar data for lighter and medium mass NSs but cooling is
very fast for heavier NS. For DM admixed DD2 EOS, it is found that for all
considered NS masses, all chosen DM masses and Fermi momenta agree well with
the observational data of PSR B0656+14, Geminga, Vela, PSR B1706-44 and PSR
B2334+61. Cooling becomes faster as compared to normal NSs in case of
increasing DM mass and Fermi momenta. It is infered from the calculations that
if low mass super cold NSs are observed in future that may support the fact
that heavier WIMP can be present inside neutron stars.Comment: 24 Pages, 15 Figures and 2 Tables. Version accepted in The European
Physical Journal
Higgs boson production in photon-photon collision at ILC: a comparative study in different little Higgs models
We study the process \gamma\gamma->h->bb_bar at ILC as a probe of different
little Higgs models, including the simplest little Higgs model (SLH), the
littlest Higgs model (LH), and two types of littlest Higgs models with T-parity
(LHT-I, LHT-II). Compared with the Standard Model (SM) prediction, the
production rate is found to be sizably altered in these little Higgs models
and, more interestingly, different models give different predictions. We find
that the production rate can be possibly enhanced only in the LHT-II for some
part of the parameter space, while in all other cases the rate is suppressed.
The suppression can be 10% in the LH and as much as 60% in both the SLH and the
LHT-I/LHT-II. The severe suppression in the SLH happens for a large \tan\beta
and a small m_h, in which the new decay mode h->\eta\eta (\eta is a light
pseudo-scalar) is dominant; while for the LHT-I/LHT-II the large suppression
occurs when f and m_h are both small so that the new decay mode h->A_H A_H is
dominant. Therefore, the precision measurement of such a production process at
the ILC will allow for a test of these models and even distinguish between
different scenarios.Comment: Version in JHEP (h-g-g & h-gamma-gamma expressions added
Azimuthal anisotropy and correlations at large transverse momenta in and Au+Au collisions at = 200 GeV
Results on high transverse momentum charged particle emission with respect to
the reaction plane are presented for Au+Au collisions at =
200 GeV. Two- and four-particle correlations results are presented as well as a
comparison of azimuthal correlations in Au+Au collisions to those in at
the same energy. Elliptic anisotropy, , is found to reach its maximum at
GeV/c, then decrease slowly and remain significant up to
-- 10 GeV/c. Stronger suppression is found in the back-to-back
high- particle correlations for particles emitted out-of-plane compared to
those emitted in-plane. The centrality dependence of at intermediate
is compared to simple models based on jet quenching.Comment: 4 figures. Published version as PRL 93, 252301 (2004
Azimuthal anisotropy in Au+Au collisions at sqrtsNN = 200 GeV
The results from the STAR Collaboration on directed flow (v_1), elliptic flow
(v_2), and the fourth harmonic (v_4) in the anisotropic azimuthal distribution
of particles from Au+Au collisions at sqrtsNN = 200 GeV are summarized and
compared with results from other experiments and theoretical models. Results
for identified particles are presented and fit with a Blast Wave model.
Different anisotropic flow analysis methods are compared and nonflow effects
are extracted from the data. For v_2, scaling with the number of constituent
quarks and parton coalescence is discussed. For v_4, scaling with v_2^2 and
quark coalescence is discussed.Comment: 26 pages. As accepted by Phys. Rev. C. Text rearranged, figures
modified, but data the same. However, in Fig. 35 the hydro calculations are
corrected in this version. The data tables are available at
http://www.star.bnl.gov/central/publications/ by searching for "flow" and
then this pape
ER-Bound Protein Tyrosine Phosphatase PTP1B Interacts with Src at the Plasma Membrane/Substrate Interface
PTP1B is an endoplasmic reticulum (ER) anchored enzyme whose access to substrates is partly dependent on the ER distribution and dynamics. One of these substrates, the protein tyrosine kinase Src, has been found in the cytosol, endosomes, and plasma membrane. Here we analyzed where PTP1B and Src physically interact in intact cells, by bimolecular fluorescence complementation (BiFC) in combination with temporal and high resolution microscopy. We also determined the structural basis of this interaction. We found that BiFC signal is displayed as puncta scattered throughout the ER network, a feature that was enhanced when the substrate trapping mutant PTP1B-D181A was used. Time-lapse and co-localization analyses revealed that BiFC puncta did not correspond to vesicular carriers; instead they localized at the tip of dynamic ER tubules. BiFC puncta were retained in ventral membrane preparations after cell unroofing and were also detected within the evanescent field of total internal reflection fluorescent microscopy (TIRFM) associated to the ventral membranes of whole cells. Furthermore, BiFC puncta often colocalized with dark spots seen by surface reflection interference contrast (SRIC). Removal of Src myristoylation and polybasic motifs abolished BiFC. In addition, PTP1B active site and negative regulatory tyrosine 529 on Src were primary determinants of BiFC occurrence, although the SH3 binding motif on PTP1B also played a role. Our results suggest that ER-bound PTP1B dynamically interacts with the negative regulatory site at the C-terminus of Src at random puncta in the plasma membrane/substrate interface, likely leading to Src activation and recruitment to adhesion complexes. We postulate that this functional ER/plasma membrane crosstalk could apply to a wide array of protein partners, opening an exciting field of research
Rapidity and Centrality Dependence of Proton and Anti-proton Production from Au+Au Collisions at sqrt(sNN) = 130GeV
We report on the rapidity and centrality dependence of proton and anti-proton
transverse mass distributions from Au+Au collisions at sqrt(sNN) = 130GeV as
measured by the STAR experiment at RHIC. Our results are from the rapidity and
transverse momentum range of |y|<0.5 and 0.35 <p_t<1.00GeV/c. For both protons
and anti-protons, transverse mass distributions become more convex from
peripheral to central collisions demonstrating characteristics of collective
expansion. The measured rapidity distributions and the mean transverse momenta
versus rapidity are flat within |y|<0.5. Comparisons of our data with results
from model calculations indicate that in order to obtain a consistent picture
of the proton(anti-proton) yields and transverse mass distributions the
possibility of pre-hadronic collective expansion may have to be taken into
account.Comment: 4 pages, 3 figures, 1 table, submitted to PR
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