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We present the analysis and comparison of predictions of the main codes for electroweak radiative corrections for the Drell-Yan process in the high lepton pair invariant mass region.
We study the physics potential of a neutrino superbeam experiment with a 2540 km baseline. We assume a neutrino beam similar to the NuMI beam in the medium energy configuration. We consider a 100 kton totally active scintillator detector at a 7 mr off-axis location. We find that such a configuration has an outstanding hierarchy discriminating capability. In conjunction with the data from the present reactor neutrino experiments, it can determine the neutrino mass hierarchy at the 3{sigma} level in less than 5 years, if sin{sup 2}2{theta}{sub 13}{>=}0.01, running in the neutrino mode alone. As a stand alone experiment, with a 5 year neutrino run and a 5 year anti-neutrino run, it can determine non-zero {theta}{sub 13} at the 3{sigma} level if sin{sup 2} 2{theta}{sub 13}{>=}7x10{sup -3} and hierarchy at the 3{sigma} level if sin{sup 2}2{theta}{sub 13}{>=}8x10{sup -3}. This data can also distinguish {delta}{sub CP} = {pi}/2 from the CP conserving values of 0 and {pi}, for sin{sup 2}2{theta}{sub 13}{>=}0.02.
The NOvA experiment is designed to search for a non-vanishing mixing angle {theta}{sub 13} with unprecedented sensitivity and has the potential to resolve the neutrino mass hierarchy and constrain CP-violation phase. NO{theta}A will use two functionally identical detectors at near and far locations to eliminate sensitivity to modeling of neutrino flux and cross-sections. The near detector will measure neutrino rate to constrain backgrounds expected in the far detector which will search for appearance of electron neutrinos and/or anti-neutrinos using Fermilab NuMI neutrino beam. This report describes initial thoughts on how the available beams and detectors may be used to reach the NOvA goals.
The new FAIR facility in Darmstadt has a broad program in the field of hadron and nuclear physics utilizing ion beams with unprecedented intensity and accuracy. The hadron physics program centers around the the high-energy storage ring HESR for antiprotons and the PANDA experiment that is integrated in it. The physics program includes among others topics like hadron spectroscopy in the charmonium mass region and below, hyperon physics, electromagnetic processes and charm in nuclei.
Our progress in computing the spectrum of excited baryons and mesons in lattice QCD is described. Sets of spatially-extended hadron operators with a variety of different momenta are used. A new method of stochastically estimating the low-lying effects of quark propagation is utilized which allows reliable determinations of temporal correlations of both single-hadron and multi-hadron operators. The method is tested on the isoscalar mesons in the scalar, pseudoscalar, and vector channels, and on the two-pion system of total isospin I = 0,1,2.
Three-quark nucleon interpolating fields in QCD have well-defined SU{sub L}(3)xSU{sub R}(3) and U{sub A}(1) chiral transformation properties, viz. [(6,3)+(3,6)], [(3,3-bar)+(3-bar,3)], [(8,1)+(1,8)] and their 'mirror' images. It has been shown (phenomenologically) in Ref. [2] that mixing of the [(6,3)+(3,6)] chiral multiplet with one ordinary ('naive') and one 'mirror' field belonging to the [(3,3-bar)+(3-bar,3)], [(8,1)+(1,8)] multiplets can be used to fit the values of the isovector (g{sub A}{sup (3)}) and the flavor-singlet (isoscalar) axial coupling (g{sub A}{sup (0)}) of the nucleon and then predict the axial F and D coefficients, or vice versa, in reasonable agreement with experiment. In an attempt to derive such mixing from an effective Lagrangian, we construct all SU{sub L}(3)xSU{sub R}(3) chirally invariant non-derivative one-meson-baryon interactions and then calculate the mixing angles in terms of baryons' masses. It turns out that there are (strong) selection rules: for example, there is only one non-derivative chirally symmetric interaction between J 1/2 fields belonging to the [(6,3)+(3,6)] and the [(3,3-bar)+(3-bar,3)] chiral multiplets, that is also U{sub A}(1) symmetric. We also study the chiral interactions of the [(3,3-bar)+(3-bar,3)] and [(8,1)+(1,8)] nucleon fields. Again, there are selection rules that allow only one off-diagonal non-derivative chiral SU{sub L}(3)xSU{sub R}(3) interaction of this type, that also explicitly breaks the U{sub A}(1) symmetry. We use this interaction to calculate the corresponding mixing angles in terms of baryon masses and fit two lowest lying observed nucleon (resonance) masses, thus predicting the third (J = 1/2, I = 3/2){Delta} resonance, as well as one or two flavor-singlet {Lambda} hyperon(s), depending on the type of mixing. The effective chiral Lagrangians derived here may be applied to high density matter calculations.
We study a nonlocal extension of the so-called Polyakov Nambu-Jona-Lasinio model at finite temperature and chemical potential, considering the impact of the presence of dynamical quarks on the scale parameter appearing in the Polyakov potential. Both real and imaginary chemical potentials are considered. The effect of varying the current quark mass is also investigated.
I review the use of cosmological large-scale structure to measure properties of neutrinos and other relic populations of light relativistic particles. With experiments to measure the anisotropies of the cosmic microwave anisotropies and the clustering of matter at low redshift, we now have securely measured a relativistic background with density appropriate to the cosmic neutrino background. Our limits on the mass of the neutrino continue to shrink. Experiments coming in the next decade will greatly improve the available precision on searches for the energy density of novel relativistic backgrounds and the mass of neutrinos.
The analysis of theories with non-minimal coupling of Higgs field to gravity revealed that they enter into strong coupling regime above certain Higgs-dependent cutoff, which may be considerably below the Planck scale. Assuming that the effective theory, complementing the Standard Model or its minimal extension — the νMSM — contains a set of higher dimensional operators suppressed by the Higgs-dependent cutoff, we analyse the reheating of the Universe after the Higgs inflation. We show that extra terms do not spoil the Higgs inflation, but can lead to baryogenesis and to warm sterile neutrino dark matter production at the reheating stage of the Universe expansion. They can also result in neutrino mass generation and proton decay.
In accelerator neutrino experiments, neutrino-mixing parameters are extracted from the counting rates of quasielastic (anti)neutrino scattering on nuclear targets. We discuss the uncertainties of these rates in the model approach with an energy-dependent (or running) axial mass of the nucleon.
The fundamental importance of searching for neutrinoless double-beta decay (0{nu}{beta}{beta}-decay) is widely recognized. Observation of the decay would tell us that the total lepton number is not conserved and that, consequently, neutrinos are massive Majorana fermions. The 0{nu}{beta}{beta}-decay is discussed in context of neutrino oscillation data. The perspectives of the experimental 0{nu}{beta}{beta}-decay searches are analyzed. The importance of reliable determination of the 0{nu}{beta}{beta}-decay nuclear matrix elements is pointed out.
Seesaw mechanism provides a natural explanation of light neutrino masses through suppression of heavy seesaw scale. In inverse seesaw models the seesaw scale can be much lower than that in the usual seesaw models. If terms inducing seesaw masses are further induced by loop corrections, the seesaw scale can be lowered to be in the range probed by experiments at the LHC without fine tuning. This talk, presented by X-G He, discuss models constructed in a recent preprint by us (arxiv:201207.6308) in which neutrino masses are generated at two loop level through inverse seesaw mechanism. These models also naturally have dark matter candidates. Although the recent data from Xenon100 put stringent constraint on the models, they can be consistent with data on neutrino masses, mixing, dark matter relic density and direct detection.
Since about a decade the european physics community interested in neutrino and neutrino-astrophysics develops a plan to conceive the next generation large underground neutrino observatory. Recently, the LAGUNA-LBNO collaboration made the outcome of the FP7 design study public which shows a clear path for the realization of such experiment. In this paper the LAGUNA and LAGUNA-LBNO Design studies, resulting in a proposal for the LBNO experiment, will be discussed. The author will focus on the long baseline neutrino oscillation search, especially on the potential to discover the neutrino mass ordering and the search for CP violation in the lepton sector.
Considering the nonzero mass effect of the target in extracting polarized parton distribution functions (PPDFs) in preasymptotic region is not negligible. We extract PPDFs from available proton structure function data and study the numerical effects of target mass corrections (TMCs). PPDFs with and without this correction are compared.
Within the “nuclear medium cooling” scenario of neutron stars all reliably known temperature—age data, including those of the central compact objects in the supernova remnants of Cassiopeia A and XMMU-J1732, can be comfortably explained by a set of cooling curves obtained by variation of the star mass within the range of typical observed masses. The recent measurements of the masses of the pulsars PSR J1616-2230, PSR J0348-0432 and J00737-3039B and the companion of J1756-2251 provide independent proof for the existence of neutron stars with masses in a broad range from 1.2 to 2M{sub ⊙} The values M > 2M{sub ⊙} call for sufficiently stiff equations of state for neutron star matter. We investigate the response of the set of neutron star cooling curves to a stiffening of the nuclear equation of state so that maximum masses of about 2.4M{sub ⊙} would be accessible and to a deconfinement phase transition from such stiff nuclear matter in the outer core to color superconducting quark matter in the inner core. Without a readjustment of cooling inputs the mass range required to cover all cooling data for the stiff DD2 equation of state should include masses of 2.426M{sub ⊙} for describing the fast cooling of CasA while the existence of a quark matter core accelerates the cooling so that CasA cooling data are described with a hybrid star of mass 1.674M{sub ⊙}.
Chiral symmetry, which is spontaneously broken in vacuum, is predicted to be partially restored in ordinary nuclear matter. The properties of vector mesons, such as their masses and/or widths are expected to change in the medium. The photoproduction reaction off nuclei is a very clean way of producing the {rho}, {omega} and {phi} mesons, and detect them via their hadronic or leptonic decays. The leptonic decay to e{sup +}e{sup -} has a small branching ratio but has the advantage of being free from final state interactions. One critical aspect in all these experiments is the correct determination of the shape and magnitude of the combinatorial background. The in-medium mass distributions and yields are compared to those measured in vacuum. No significant shift is observed in the masses of the mesons, however substantial increase in their widths is reported.
We show that, by taking a bare mass spectrum with constant spacings for the quark-antiquark propagators, which is subject to considerable mass shifts from meson loops, one adequately describes a large variety of mesonic resonances, from the light scalars to the bb-bar states. All our results indicate that a harmonic-oscilator spectrum with universal frequency, in combination with coupled-channel effects, does a much better job than the qq-bar spectrum of the funnel potential.
Charge symmetry is an approximate symmetry of the strong interaction. Studies of its breaking can yield information on the u and d quark mass difference. A theoretical collaboration is currently working on the description of charge symmetry breaking mechanisms for dd{yields}{alpha}{pi}{sup 0} and np{yields}d{pi}{sup 0} within Chiral Perturbation Theory, using the data from TRI-UMF and IUCF. One of the items in the program of the WASA-at-COSY collaboration is to extend the data base for the dd{yields}{alpha}{pi}{sup 0} reaction to higher energies, which would allow the extraction of the information on the p-wave. Status of the analysis of experimental data along with the preliminary results from the pilot run will be presented here.