15202458
Matter effects of thin layers: Detecting oil by oscillations of solar neutrinos
We consider a possibility to use the solar neutrinos for studies of small scale structures of the Earth and for geological research. Effects of thin layers of matter with density contrast on oscillations of Beryllium neutrinos inside the Earth are studied. We find that change of the $^7Be$ neutrino flux can reach 0.1 % for layers with density of oil and size 20 km. Problems of detection are discussed. Hypothetical method would consist of measuring the $^7Be -$ flux by, {\it e.g.}, large deep underwater detector$-$submarine which could change its location.
115887973
Solar neutrinos: Theoretical aspects
31519375
Multiple spectral splits of supernova neutrinos.
Collective oscillations of supernova neutrinos swap the spectra f(nu(e))(E) and f(nu[over ](e))(E) with those of another flavor in certain energy intervals bounded by sharp spectral splits. This phenomenon is far more general than previously appreciated: typically one finds one or more swaps and accompanying splits in the nu and nu[over ] channels for both inverted and normal neutrino mass hierarchies. Depending on an instability condition, swaps develop around spectral crossings (energies where f(nu(e))=f(nu(x)), f(nu[over ](e))=f(nu[over ](x)) as well as E-->infinity where all fluxes vanish), and the widths of swaps are determined by the spectra and fluxes. Washout by multiangle decoherence varies across the spectrum and splits can survive as sharp spectral features.
59164737
Recent developments in neutrino phenomenology
The first phase of studies of the neutrino mass and mixing is essentially over. The outcome is the discovery of non-zero neutrino mass and determination of the dominant structure of the lepton mixing matrix. In some sense this phase was very simple, and nature was very collaborative with us: Two main effects - the vacuum oscillations and the adiabatic conversion in matter (the MSW-effect) - provide complete interpretation of the experimental results. Furthermore, with the present accuracy of measurements the $3\nu-$mixing analysis is essentially reduced to the $2\nu$ consideration. I will present a concise and comprehensive description of this first phase. The topics include: (i) the concept of neutrino mixing in vacuum and matter; (ii) physics of the oscillations and adiabatic conversion; (iii) the experimental evidences of the flavor transformations and determination of the oscillation parameters. Some implications of the obtained results are discussed. Comments are given on the next phase of the field that will be much more involved.
18492548
Pontecorvo's original oscillations revisited
Abstract We show that a left-handed neutrino ν L can oscillate into its CPT -conjugate state ν R with maximal amplitude, in direct analogy with K 0 − K 0 oscillations. Peculiarities of such oscillations under different conditions are studied.
119540272
Self-induced spectral splits in supernova neutrino fluxes
In the dense-neutrino region above the neutrino sphere of a supernova (r < or approx. 400 km), neutrino-neutrino refraction causes collective flavor transformations. They can lead to 'spectral splits' where an energy E{sub split} splits the transformed spectrum sharply into parts of almost pure but different flavors. Unless there is an ordinary MSW resonance in the dense-neutrino region, E{sub split} is determined by flavor-lepton number conservation alone. Spectral splits are created by an adiabatic transition between regions of large and small neutrino density. We solve the equations of motion in the adiabatic limit explicitly and provide analytic expressions for a generic example.
119111785
Applications of FIESTA
Sector decomposition in its practical aspect is a constructive method used to evaluate Feynman integrals numerically. We present a new program performing the sector decomposition and integrating the expression afterwards. The program can be also used in order to expand Feynman integrals automatically in limits of momenta and masses with the use of sector decompositions and Mellin--Barnes representations. The program is parallelizable on modern multicore computers and even on multiple computers. Also we demonstrate some new numerical results for four-loop massless propagator master integrals.
119247211
The static quark potential to three loops in perturbation theory
The static potential constitutes a fundamental quantity of Quantum Chromodynamics. It has recently been evaluated to three-loop accuracy. In this contribution we provide details on the calculation and present results for the 14 master integrals which contain a massless one-loop insertion.
118355424
Chiral color symmetry and $G'$-boson mass limit from Tevatron data on $t \bar t$-production
A gauge model with chiral color symmetry of quarks is considered and possible effects of the color $G'$-boson octet predicted by this symmetry are investigated. The contributions of the $G'$-boson to the cross section $\sigma_{t\bar{t}}$ and to the forward-backward asymmetry $A_{\rm FB}^{p \bar p}$ of $t\bar{t}$ production at the Tevatron are calculated and analysed in dependence on two free parameters of the model, the mixing angle $\theta_G$ and $G'$ mass $m_{G'}$. The $G'$-boson contributions to $\sigma_{t\bar{t}}$ and $A_{\rm FB}^{p \bar p}$ are shown to be consistent with the Tevatron data on $\sigma_{t\bar{t}}$ and $A_{\rm FB}^{p \bar p}$, the allowed region in the $m_{G'} - \theta_G$ plane is discussed and around $m_{G'}=1.2 \, TeV, \; \theta_G=14^\circ $ the region of $1 \sigma$ consistency is found.
2122861
Decoupling of heavy quarks in HQET
Decoupling of c-quark loops in b-quark HQET is considered. The decoupling coefficients for the HQET heavy-quark field and the heavy–light quark current are calculated with the three-loop accuracy. The last result can be used to improve the accuracy of extracting fB from HQET lattice simulations (without c-quark loops). The decoupling coefficient for the flavour-nonsinglet QCD current with n antisymmetrized γ-matrices is also obtained at three loops; the result for the tensor current (n = 2) is new.
58945450
Optical measurement of transverse laser cooling with synchro-betatron coupling
Laser cooling experiment of transverse direction for Mg is performed at the small ion storage and cooler ring, S-LSR. We measured horizontal beam size with CCD camera, and longitudinal momentum spread with PAT (Post Acceleration Tube). The measured beam size with CCD camera is decreased from about 1mm to 0.55mm and longitudinal momentum spread measured with PAT increased near the resonant condition. This suggests transverse temperature was transferred to longitudinal direction with synchro-betatron coupling. INTRODUCTION There are several methods to cool ion beam, such as stochastic cooling, electron beam cooling, and laser cooling. Among these methods, laser cooling can achieve the lowest temperature due to its very strong cooling force. The first experiment of laser cooling of ion beam was carried out at TSR [1], and followed at ASTRID [2]. In laser cooling method, a laser is co-propagating or counter-propagating with the ion beam. Since momentum transfer between the laser and the ion beam occurs longitudinally, we can cool the beam particles mainly in the longitudinal direction. Although intra-beam scattering cools the beam transversely, cooling power is weak in usual particle density [3]. Resonant coupling method is proposed to cool ion beam transversely [4]. In the cases betatron tunes (νx, νy) and synchrotron tune νs have the following relations, νs νx = integer νx νy = integer, and there is energy change at a position with a finite dispersion, laser cooling power transmits to transverse direction. In a storage ring, if cooling power is stronger than heating power, beam will be cooled 3-dimensinally. To realize such beam crystallization, the lattice must be properly designed. A small laser-equipped storage ring (SLSR) (Fig. 1) was constructed for this purpose [5]. The principal parameters of S-LSR, the beam and the laser used in the experiment are shown in Table 1.