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We study transverse momentum dependent parton distribution functions (TMDs) with non-local operators in lattice QCD, using MILC/LHPC lattices. Results obtained with a simplified operator geometry show visible dipole deformations of spin-dependent quark momentum densities.
Unlike the proton, whose parton distributions have been extracted using abundant data, the pion has been relatively ignored. The pion, nevertheless, is a crucial part of the current understanding of the nucleon's parton distributions and of the binding of the nucleon into a nucleus. The pion's structure becomes more intriguing when its dual roles as a light quark-antiquark system and as QCD's Goldstone boson are considered. One source of data on the pion's structure is pion-induced Drell-Yan scattering. Two recent re-analyses of such data are discussed here.
The results of a recent next-to-leading order QCD analysis of the world data on polarized deep inelastic scattering are reported. New parameterizations are derived for the quark and gluon distributions, accounting for the massive Wilson coefficient for the charm quarks, and the value of {alpha}{sub s}(M{sub z}{sup 2}) is determined with correlated errors. We obtain {alpha}{sub s}{sup NLO}(M{sub Z}{sup 2}) = 0.1132{sub -0.0095}{sup +0.0056}. Limits on potential higher twist contributions to the structure function g{sub 1}(x,Q{sup 2}) are derived. We also compare to the results obtained by other groups.
We review recent progress in the study of quark-hadron duality in electron-nucleon structure functions. New developments include insights into the local aspects of duality obtained using truncated moments of structure functions, which allow duality-violating higher-twist contributions to be identified in individual resonance regions. Preliminary studies of pion electropro-duction have also showed the first glimpses of duality in semi-inclusive cross sections, which if confirmed would greatly expand the scope of constraining the flavor and spin dependence of parton distributions.
Neutrino oscillation results and their robustnes are briefly reviewed, along with neutrino mass generation schemes, from high to low-scale seesaw, with and without supersymmetry, as well as phenomenological implications.
In this talk, the performance comparison among superbeams (SB), beta beams (BB), and the Neutrino Factory (NF) is discussed. The ingredients to such a comparison are described, and the optimization and status of BB and NF are addressed. Finally, one example for the performance comparison is shown.
A summary of the present status of the charged lepton flavor violation search with muons is presented. The relevant measurements (g-2){sub {mu}}, the {mu} {sup +}{yields} e{sup +} {gamma} decay and the direct muon-to-electron conversion projects are briefly reviewed.
The neutrino spectra from a future galactic core collapse supernova could reveal information on the neutrino mixing pattern, especially on {theta}{sub 13} and the mass hierarchy. I briefly outline our current understanding of neutrino flavor conversions inside a supernova, and point out possible signatures of various neutrino mixing scenarios that the neutrino detectors should look for. Supernova neutrinos provide a probe for {theta}{sub 13} and mass hierarchy that is complementary to, and sometimes even better than, the current and proposed terrestrial neutrino oscillation experiments.
The OPERA experiment is aiming at the first direct detection of neutrino oscillations in appearance mode through the study of the v{sub {mu}}{yields}v{tau} channel. The OPERA detector is placed in the CNGS long baseline v{sub {mu}} beam 730 km away from the neutrino source. The analysis of a sub-sample of the data taken in the 2008-2009 runs was completed After a brief description of the beam and the experimental setup, we report on event analysis and on a first candidate event, its background estimation and statistical significance.
The recently observed event excess in MiniBooNE anti-neutrino data is in agreement with the LSND evidence for electron anti-neutrino appearance. We propose an explanation of these data in terms of a (3+1) scheme with a sterile neutrino including non-standard neutrino interactions (NSI) at neutrino production and detection. The interference between oscillations and NSI provides a source for CP violation which we use to reconcile different results from neutrino and anti-neutrino data. Our best fit results imply NSI at the level of a few percent relative to the standard weak interaction, in agreement with current bounds. We compare the quality of the NSI fit to the one obtained within the (3+1) and (3+2) pure oscillation frameworks.
We study the effects of one additional sterile neutrino at the Neutrino Factory. On the one hand, we do not impose any constraint on the additional mass squared splitting, which is different from earlier discussions where LSND motivated Q(1)eV{sup 2} is always assumed. We find that a combination of near detectors and long baselines is good at searching for arbitrarily massive sterile neutrinos at the neutrino factory. On the other hand, we compare our sensitivities of mixing angles with the MINOS results where |{Delta}m{sub 41}{sup 2}|>>{Delta}m{sub 31}{sup 2}| is assumed and the fast oscillations in the far detectors are averaged out.
The atmospheric-neutrino sample at Super-Kamiokande is sensitive to all neutrino oscillation parameters. Our recent analyses focus on the sub-dominant effects which includes unknown parameters. The upper limit to {theta}{sub 13} is set to be sin{sup 2}{theta}{sub 13}<0.066 (< 0.122) at 90% confidence level in case of the normal (inverted) mass hierarchy. We confirm our sample has the sensitivity to the CP phase, {delta}{sub CP}. The mass hierarchy test also is performed. CPT violation in the neutrino oscillation is tested with the atmospheric-neutrino sample. However, our result suggests the CPT conservation.
The so-called Non-Standard v-Interactions in propagation is a widely studied topic in the Neutrino Factory literature. However, special attention has not been paid to the possible correlation effects among the whole set of parameters arising in this context (standard and non-standard ones). Here we will focus on these correlation effects analysing the performance of three different Neutrino Factory setups. In addition, we explore the new avenues of CP violation coming from this sort of Non-Standard v-Interactions with the same perspective, in other words, studying the relation among the several CP-phases involved.
The present theoretical status of neutrino interactions in the few-GeV region is reviewed. Quasielastic scattering, pion production and their importance for neutrino oscillation studies are discussed, making emphasis on the open questions that arise in the comparison with new experimental data.
We propose a new process of {mu}{sup -}e{sup -}{yields}e{sup -}e{sup -} in a muonic atom for a quest of charged lepton flavor violation. This is based on the work[1]
Emulsion technologies are very much developed in the last decade and still developing in both the emulsion gel and the data taking. Emulsion detectors are suitable for the neutrino experiments because they can distinguish all 3 flavors of neutrino. The OPERA experiment, a recent pillar in the emulsion experiments aiming at the first observation of the neutrino oscillation in CNGS beam in appearance mode, is running, showing the good capability to separate 3 flavor neutrino interactions. In this poster, the recent developments and prospects of the emulsions for the next generation experiments are reported.
Transverse-momentum-dependent parton distributions (TMDs) provide three-dimensional images of the partonic structure of the nucleon in momentum space. We made impressive progress in understanding TMDs, both from the theoretical and experimental point of view. This brief overview on TMDs is divided in two parts: in the first, an essential list of achievements is presented. In the second, a selection of open questions is discussed.
It is reported on an analysis of electroproduction of light mesons at small Bjorken-x (x{sup Bj}) within the handbag approach. The partonic subprocesses, meson electroproduction off quarks or gluons, are calculated within the modified per-turbative approach (m.p.a.) in which quark transverse momenta are retained. The soft hadronic matrix elements, generalized parton distributions (GPDs), are constructed by means of double distributions. The constraints from parton distributions and sum rules are taken into account. Various moments of these GPDs are compared to recent results from lattice gauge theories.