Showing papers in "Nuovo Cimento Della Societa Italiana Di Fisica A-nuclei Particles and Fields in 2013"
TL;DR: For example, the atmospheric neutrino flux cannot accommodate an excess of 28 neutrinos observed with energies above 60 TeV as discussed by the authors, which is the first evidence for a flux of high-energy neutrs of cosmic origin.
Abstract: Developments in neutrino astronomy have been to a great extent motivated by the search for the sources of the cosmic rays, leading at a very early stage to the concept of a cubic kilometer neutrino detector. Almost four decades later such an instrument, IceCube, is taking data and has produced the first evidence for a flux of high-energy neutrinos of cosmic origin. After a brief review of the history of the field, we will introduce IceCube and describe the first analysis of data taken with the completed instrument. The atmospheric neutrino flux cannot accommodate an excess of 28 neutrinos observed with energies above 60 TeV. We will briefly speculate on the origin of these events. Readers interested specifically in IceCube results may refer directly to Sect. 3. (© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
8 citations
TL;DR: In this paper, the phenomenological access of generalized parton distributions from photon and meson electroproduction off proton was reported, emphasizing the role of HERMES data for deeply virtual Compton scattering, which allows to map various asymmetries into the space of Compton form factors.
Abstract: We report on the status of the phenomenological access of generalized parton distributions from photon and meson electroproduction off proton. Thereby, we emphasize the role of HERMES data for deeply virtual Compton scattering, which allows us to map various asymmetries into the space of Compton form factors.
6 citations
6 citations
5 citations
TL;DR: In this article, the conformal properties of AdS space, the properties of a field theory in one dimension under the full conformal group found by de Alfaro, Fubini and Furlan, and the frame-independent single-variable light-front Schr¨odinger equation for bound states all lead to the same result: a relativistic nonperturbative model which successfully incorporates salient features of hadronic physics, including confinement, linear Regge trajectories, and results which are conventionally attributed to spontaneous chiral symmetry breaking.
Abstract: We show that (a) the conformal properties of Anti-de Sitter (AdS) space, (b) the properties of a field theory in one dimension under the full conformal group found by de Alfaro, Fubini and Furlan, and (c) the frame-independent singlevariable light-front Schr¨odinger equation for bound states all lead to the same result: a relativistic non-perturbative model which successfully incorporates salient features of hadronic physics, including confinement, linear Regge trajectories, and results which are conventionally attributed to spontaneous chiral symmetry breaking.
4 citations
TL;DR: The 3rd Workshop on the QCD Structure of the Nucleon (QCD-N'12), 22-26 October 2012, Bilbao, Spain this paper, was the first workshop dedicated to the structure of the nucleon.
Abstract: Additional references included. Invited talk at the 3rd Workshop on the QCD Structure of the Nucleon (QCD-N'12), 22-26 October 2012, Bilbao, Spain. 8 pages & 14 figures
4 citations
TL;DR: In this article, the current status of cosmological bounds on neutrino properties and the potential of future observations, for example by the recently approved EUCLID mission, are reviewed.
Abstract: In recent years precision cosmology has become an increasingly powerful probe of particle physics. Perhaps the prime example of this is the very stringent cosmological upper bound on the neutrino mass. However, other aspects of neutrino physics, such as their decoupling history and possible non-standard interactions, can also be probed using observations of cosmic structure. Here, I review the current status of cosmological bounds on neutrino properties and discuss the potential of future observations, for example by the recently approved EUCLID mission, to precisely measure neutrino properties.
3 citations
TL;DR: In this article, the authors considered direct diphoton production in hadron collisions and computed the next-to-next-leading order (NNLO) radiative corrections at the fully-differential level.
Abstract: We consider direct diphoton production in hadron collisions. We compute the next-to-next-to-leading order (NNLO) QCD radiative corrections at the fully-differential level. Our calculation is based on the q_T subtraction formalism and it is implemented in a parton level Monte Carlo program, which allows the user to apply arbitrary kinematical cuts on the final-state photons and the associated jet activity, and to compute the corresponding distributions in the form of bin histograms. We present selected numerical results related to Higgs boson searches and diphoton studies performed at the LHC and the Tevatron, and we show how the NNLO corrections to diphoton production are relevant to understand the main background of the decay channel (H -> gamma gamma) of the Higgs boson H.
2 citations
TL;DR: In this paper, double longitudinal spin asymmetries in semi-inclusive deep inelastic scattering using a new dedicated Monte Carlo generator, which includes quark intrinsic transverse momentum within the generalized parton model based on the fully differential cross section for the process.
Abstract: We present studies of double longitudinal spin asymmetries in semi-inclusive deep inelastic scattering using a new dedicated Monte Carlo generator, which includes quark intrinsic transverse momentum within the generalized parton model based on the fully differential cross section for the process. Additionally, we apply Bessel-weighting to the simulated events to extract transverse momentum dependent parton distribution functions and also discuss possible uncertainties due to kinematic correlation effects.
2 citations
TL;DR: In this paper, the authors present the latest results on these searches and the comparison with LHC searches and compare the results of these searches with the results from the Fermi Gamma-ray Space Telescope.
Abstract: Summary. — Can we learn about New Physics with astronomical and astro- particle data? Since its launch in 2008, the Large Area Telescope, onboard of the Fermi Gamma-ray Space Telescope, has detected the largest amount of gamma rays in the 20 MeV - 300 GeV energy range and electrons + positrons in the 7 GeV- 1 TeV range. These impressive statistics allow one to perform a very sensitive indirect experimental search for dark matter. We will present the latest results on these searches and the comparison with LHC searches.
2 citations
TL;DR: In this paper, the conceptual basis for understanding the interplay of neutrino mass and mixing for neutrinos oscillations were paradoxically discussed in a period when the prevailing view was that of massless neutrions.
Abstract: The conceptual basis for understanding the interplay of neutrino mass and mixing for neutrino oscillations were paradoxically discussed in a period when the prevailing view was that of massless neutrinos. The name of Bruno Pontecorvo is associated to most of the components for this beautiful quantum phenomenon: muon-electron universality, different neutrino flavours, mismatch between weak interaction and mass eigenstates, neutrino oscillation phenomenology, including flavour and Majorana transitions. 1 ar X iv :1 31 2. 74 51 v1 [ he pph ] 2 8 D ec 2 01 3
TL;DR: In this article, the authors discuss the significance of charm dynamics in an era when the Standard Model is well established in its degrees of freedom but little understood in quite a few of its different parts.
Abstract: We shall proceed to discuss the significance of charm dynamics in an era when the Standard Model is well established in its degrees of freedom but little understood in quite a few of its different parts. The study of decays and asymmetries in the decays of mesons with charm quantum numbers provide us possible insights into the yet uncharted dynamics of the Standard Model at the GeV scale. We will discuss some interesting channels with hadrons and/or leptons in the final state, the shortcomings of theoretical structures currently advocated and future experimental prospects.
TL;DR: In this paper, generalized parton distributions (GPDs) extracted from exclusive meson leptoproduction within the handbag approach are discussed for the GPD E and the transversity ones.
Abstract: The information about generalized parton distributions (GPDs) extracted from exclusive meson leptoproduction within the handbag approach is summarized. Details are only discussed for the GPD E and the transversity ones. It is also commented on results for deep virtual Compton scattering evaluated from these GPDs
TL;DR: In this article, the transverse structure of the nucleon and partonic correlations are discussed, including hard scattering processes and correlations between spin and transverse degrees of freedom, and k{sub T}-effects with polarized SIDIS.
Abstract: This slideshow presents work on the transverse structure of the nucleon and partonic correlations. Topics include: •Hard scattering processes and correlations between spin and transverse degrees of freedom; •k{sub T}-effects with polarized SIDIS; •Higher twist effects in SIDIS.
TL;DR: A concise review of the experimental developments on neutrino mixing and their theoretical implications as presented and discussed at this Conference can be found in this article, with a focus on non-abelian flavour groups.
Abstract: We present a concise review of the experimental developments on neutrino mixing and their theoretical implications as presented and discussed at this Conference. The recent data disfavour many models but the surviving ones still span a wide range going from Anarchy (no structure, no symmetry in the neutrino sector) to a maximum of symmetry, as for the models based on discrete non-abelian flavour groups which can be improved following the indications from the recent data.
TL;DR: In this article, the authors define a universal set of TMD correlators of definite rank with a well-defined operator structure, which can be traced back to the color flow in the process.
Abstract: Transverse momentum dependent (TMD) distribution and fragmentation functions are described as Fourier transforms of matrix elementscontaining nonlocal combinations of quark and gluon fields. These matrix elements also contain a gauge link operator with a process dependent path, of which the process dependence that can be traced back to the color flow in the process. Expanding into irreducible tensors built from the transverse momenta $p_\st$, we can define a universal set of TMD correlators of definite rank with a well-defined operator structure.
TL;DR: In this article, a single-inclusive high-p_T$ jet production in unpolarized and longitudinally polarized $pp$ collisions at RHIC was investigated, investigating the effect of the algorithm adopted to define the jets on numerical results for cross sections and spin asymmetries.
Abstract: We report on a recent calculation of single-inclusive high-$p_T$ jet production in unpolarized and longitudinally polarized $pp$ collisions at RHIC, investigating the effect of the algorithm adopted to define the jets on the numerical results for cross sections and spin asymmetries.
TL;DR: In this paper, the expected results of this endeavor will provide important tests for various theoretical approaches to understand quark-antiquark interaction dynamics in bottomonium spectroscopy.
Abstract: Summary. | Bottomonium spectroscopy is a key source necessary for understanding of Quantum Chromodynamics. The expected results of this endeavor will provide important tests for various theoretical approaches to understanding quark-antiquark interaction dynamics. Recent results in bottomonium spectroscopy are presented. PACS 10.14.40.Pq { 10.14.60.Cd
TL;DR: In this paper, a simple and efficient extraction procedure of the neutron generalized parton distributions, able to take into account the nuclear effects included in IA analysis, is proposed, and it is shown how, in the low momentum transfer region, the sum of the GPDs H and E is dominated by the neutron contribution.
Abstract: Hard exclusive processes, such as Deeply Virtual Compton Scattering (DVCS), allow to access generalized parton distributions (GPDs). By means of an Impulse Approximation (IA) calculation, it is shown here how, in the low momentum transfer region, the sum of the GPDs H and E is dominated by the neutron contribution. Thanks to this property, 3He could open a new way to access the neutron structure information. In this work, a simple and efficient extraction procedure of the neutron GPDs, able to take into account the nuclear effects included in IA analysis, is proposed.
TL;DR: In this paper, the near-future and proposed longer-term accelerator-based neutrino experiments are described and discussed, as well as the current state-of-the-art.
Abstract: Near-future and proposed longer-term accelerator-based neutrino experiments are described and discussed.
TL;DR: The recent controversy on the nucleon spin decomposition problem is critically overviewed in this article, where it is shown that there exist two and only two physically invariant gauge-invariant decompositions of the NiC.
Abstract: The recent controversy on the nucleon spin decomposition problem is critically overviewed. We argue that there exist two and only two physically inequivalent gauge-invariant decompositions of the longitudinal nucleon spin, contrary to the rapidly spreading view in the QCD spin physics community that there are infinitely many decompositions of the nucleon spin.
TL;DR: In this paper, a systematic approximation scheme of QCD in which the quark model picture of hadrons emerges at lowest order was presented, and the S-matrix corrections were calculated in the usual way, but with states bound by the linear \order{\alpha_s^0} potential instead of plane waves in the in and out states.
Abstract: I briefly review a systematic approximation scheme of QCD in which the quark model picture of hadrons emerges at lowest order. A linear A^0 potential arises if Gauss' law is solved with a non-vanishing boundary condition at spatial infinity. Similarly to the Dirac case one can describe relativistic states including any number of particle pairs (sea quarks) using valence wave functions, whose norms give {\em inclusive} probability densities. Provided \alpha_s(Q^2) freezes in the infrared, perturbative corrections to the S-matrix can be calculated in the usual way, but with states bound by the linear \order{\alpha_s^0} potential instead of plane waves in the in and out states.
TL;DR: In this article, the experimental information from longitudinal single-spin asymmetries for W boson production in polarised proton-proton collisions can be included in a polarised parton determination by Bayesian reweighting of a Monte Carlo set of polarised PDF replicas.
Abstract: — We discuss how the experimental information from longitudinal single-spin asymmetries for W boson production in polarised proton-proton collisions can be included in a polarised parton determination by Bayesian reweighting of a Monte Carlo set of polarised PDF replicas. We explicitly construct a prior ensemble of polarised parton distributions using available fits to inclusive and semiinclusive DIS data and we discuss the potential impact of existing and future RHIC measurements on it.