10,591 research outputs found
High energy DVCS on a photon and related meson exclusive production
In this work we estimate the differential cross section for the high energy
deeply virtual Compton scattering on a photon target within the QCD
dipole-dipole scattering formalism. For the phenomenology, a saturation model
for the dipole-dipole cross section for two photon scattering is considered.
Its robustness is supported by good description of current accelerator data. In
addition, we consider the related exclusive vector meson production processes.
This analysis is focused on the light and meson production, which
produce larger cross sections. The phenomenological results are compared with
the theoretical calculation using the CD BFKL approach.Comment: 6 pages, 5 figures. Version to be published in Physical Review
Neutrino Mass Matrix Textures: A Data-driven Approach
We analyze the neutrino mass matrix entries and their correlations in a
probabilistic fashion, constructing probability distribution functions using
the latest results from neutrino oscillation fits. Two cases are considered:
the standard three neutrino scenario as well as the inclusion of a new sterile
neutrino that potentially explains the reactor and gallium anomalies. We
discuss the current limits and future perspectives on the mass matrix elements
that can be useful for model building.Comment: 25 pages, 18 figure
Diffractive photoproduction of heavy quarks in hadronic collisions
In this letter we study the diffractive photoproduction of heavy quarks in
hadronic (pp/pA/AA) interactions for Tevatron and LHC energies. The integrated
cross section and rapidity distribution for the process h_1 h_2 --> h_1 h_2
QQBAR (h_i = p,A and Q = c,b) are estimated using the Color Glass Condensate
(CGC) formalism. Our results indicate that this production channel has larger
cross sections than the competing reactions of double diffractive production
and coherent AA reactions initiated by two-photon collisions.Comment: 4 pages, 2 figures, 1 table. Version to be published in Physical
Review
What can we learn about the lepton CP phase in the next 10 years?
We discuss how the lepton CP phase can be constrained by accelerator and
reactor measurements in an era without dedicated experiments for CP violation
search. To characterize globally the sensitivity to the CP phase \delta_{CP},
we introduce a new measure, the CP exclusion fraction, which quantifies what
fraction of the \delta_{CP} space can be excluded at a given input values of
\theta_{23} and \delta_{CP}. Using the measure we study the CP sensitivity
which may be possessed by the accelerator experiments T2K and NOvA. We show
that, if the mass hierarchy is known, T2K and NOvA alone may exclude,
respectively, about 50%-60% and 40%-50% of the \delta_{CP} space at 90% CL by
10 years running, provided that a considerable fraction of beam time is devoted
to the antineutrino run. The synergy between T2K and NOvA is remarkable,
leading to the determination of the mass hierarchy through CP sensitivity at
the same CL.Comment: Analyses and plots improved, conclusions unchanged, 23 pages, 8
figures, 1 tabl
Flavor Gauge Models Below the Fermi Scale
The mass and weak interaction eigenstates for the quarks of the third
generation are very well aligned, an empirical fact for which the Standard
Model offers no explanation. We explore the possibility that this alignment is
due to an additional gauge symmetry in the third generation. Specifically, we
construct and analyze an explicit, renormalizable model with a gauge boson,
, corresponding to the symmetry of the third family. Having a
relatively light (in the MeV to multi-GeV range), flavor-nonuniversal gauge
boson results in a variety of constraints from different sources. By
systematically analyzing 20 different constraints, we identify the most
sensitive probes: kaon, , and Upsilon decays, mixing,
atomic parity violation, and neutrino scattering and oscillations. For the new
gauge coupling in the range the model is shown to
be consistent with the data. Possible ways of testing the model in physics,
top and decays, direct collider production and neutrino oscillation
experiments, where one can observe nonstandard matter effects, are outlined.
The choice of leptons to carry the new force is ambiguous, resulting in
additional phenomenological implications, such as non-universality in
semileptonic bottom decays. The proposed framework provides interesting
connections between neutrino oscillations, flavor and collider physics.Comment: 44 pages, 7 figures, 3 tables; B physics constraints and references
added, conclusions unchange
On the renormalization of the electroweak chiral Lagrangian with a Higgs
We consider the scalar sector of the effective non-linear electroweak
Lagrangian with a light "Higgs" particle, up to four derivatives in the chiral
expansion. The complete off-shell renormalization procedure is implemented,
including one loop corrections stemming from the leading two-derivative terms,
for finite Higgs mass. This determines the complete set of independent chiral
invariant scalar counterterms required for consistency; these include bosonic
operators often disregarded. Furthermore, new counterterms involving the Higgs
particle which are apparently chiral non-invariant are identified in the
perturbative analysis. A novel general parametrization of the pseudoescalar
field redefinitions is proposed, which reduces to the various usual ones for
specific values of its parameter; the non-local field redefinitions reabsorbing
all chiral non-invariant counterterms are then explicitly determined. The
physical results translate into renormalization group equations which may be
useful when comparing future Higgs data at different energies
Actin assembly ruptures the nuclear envelope by prying the lamina away from nuclear pores and nuclear membranes in starfish oocytes.
The nucleus of oocytes (germinal vesicle) is unusually large and its nuclear envelope (NE) is densely packed with nuclear pore complexes (NPCs) stockpiled for embryonic development. We showed that breakdown of this specialized NE is mediated by an Arp2/3-nucleated F-actin 'shell' in starfish oocytes, in contrast to microtubule-driven tearing in mammalian fibroblasts. Here, we address the mechanism of F-actin-driven NE rupture by correlated live-cell, super-resolution and electron microscopy. We show that actin is nucleated within the lamina sprouting filopodia-like spikes towards the nuclear membranes. These F-actin spikes protrude pore-free nuclear membranes, whereas the adjoining membrane stretches accumulate NPCs associated with the still-intact lamina. Packed NPCs sort into a distinct membrane network, while breaks appear in ER-like, pore-free regions. Thereby, we reveal a new function for actin-mediated membrane shaping in nuclear rupture that is likely to have implications in other contexts such as nuclear rupture observed in cancer cells
On the Viability of Minimal Neutrinophilic Two-Higgs-Doublet Models
We study the constraints that electroweak precision data can impose, after
the discovery of the Higgs boson by the LHC, on neutrinophilic
two-Higgs-doublet models which comprise one extra doublet
and a new symmetry, namely a spontaneously broken or a softly
broken global . In these models the extra Higgs doublet, via its very
small vacuum expectation value, is the sole responsible for neutrino masses. We
find that the model with a symmetry is basically ruled out by
electroweak precision data, even if the model is slightly extended to include
extra right-handed neutrinos, due to the presence of a very light scalar. While
the other model is still perfectly viable, the parameter space is considerably
constrained by current data, specially by the parameter. In particular, the
new charged and neutral scalars must have very similar masses.Comment: 22 pages, 3 figures, references and comments added, conclusions
unchanged, matches version to appear in JHE
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