Search results for "particle physic"
showing 8 items of 6828 documents
Combining heavy quark spin and local hidden gauge symmetries in the dynamical generation of hidden charm baryons
2013
We present a coupled channel unitary approach to obtain states dynamically generated from the meson-baryon interaction with hidden charm, using constraints of heavy quark spin symmetry. As a basis of states, we use (D) over barB, (D) over bar *B states, with B baryon charmed states belonging to the 20 representations of SU(4) with J(P) = 1/2(+), 3/2(+). In addition we also include the eta N-c and J/psi N states. The inclusion of these coupled channels is demanded by heavy quark spin symmetry, since in the large m(Q) limit the D and D* states are degenerate and are obtained from each other by means of a spin rotation, under which QCD is invariant. The novelty in the work is that we use dynam…
The Minimal 3 + 2 Neutrino Model vs. Higgs Decays
2016
Abstract The minimal 3+2 neutrino model is a Type-I seesaw model with two Weyl fermions, singlets under the Standard Model. Apart from light neutrino masses and mixings, this model can be fully described by four additional parameters. In this work, we study the minimal 3+2 neutrino model in scenarios where the singlets have masses at the GeV scale. This can lead to Higgs decays into heavy neutrinos, which could be observable as displaced vertices at the LHC.
Lattice study of the Boer-Mulders transverse momentum distribution in the pion
2013
The Boer-Mulders transverse momentum-dependent parton distribution (TMD) characterizes polarized quark transverse momentum in an unpolarized hadron. Techniques previously developed for lattice calculations of nucleon TMDs are applied to the pion. These techniques are based on the evaluation of matrix elements of quark bilocal operators containing a staple-shaped Wilson connection. Results for the Boer-Mulders transverse momentum shift in the pion, obtained at a pion mass of $m_{\pi} = 518\, \mbox{MeV} $, are presented and compared to corresponding results in the nucleon.
Probing Planck scale physics with IceCube
2005
Neutrino oscillations can be affected by decoherence induced e.g. by Planck scale suppressed interactions with the space-time foam predicted in some approaches to quantum gravity. We study the prospects for observing such effects at IceCube, using the likely flux of TeV antineutrinos from the Cygnus spiral arm. We formulate the statistical analysis for evaluating the sensitivity to quantum decoherence in the presence of the background from atmospheric neutrinos, as well as from plausible cosmic neutrino sources. We demonstrate that IceCube will improve the sensitivity to decoherence effects of ${\cal O}(E^2/M_{\rm Pl})$ by 17 orders of magnitude over present limits and, moreover, that it ca…
Charmonium resonances from 2+1 flavor CLS lattices
2019
Many exotic charmonium resonances have been identified recently in experiment, however their nature and properties are mostly unknown. Algorithmic and theoretical progress in lattice calculations has enabled reliable numerical investigation of the spectrum below the strong decay threshold, while the study of charmonium resonances remains an open challenge. The main difficulty to overcome is the presence of many open decay channels which are coupled together, resulting in a complex finite volume quantization condition. We report on our recent progress towards the determination of single-channel and coupled-channel scattering matrices in the scalar and vector channels on CLS ensembles. We als…
Measurement of atmospheric neutrino oscillations with three years of data from the full sky.
2018
Initial release related to the measurement of atmospheric neutrino oscillations using three years of neutrino data from the full sky. IceCube results published in Physical Review Letters are competitive for the first time with the best measurements to date. Release limited to Δχ² maps in the (Δm², sin²(θ_23)) space for both the normal and inverted mass ordering. Additional information will be provided as follow-up data analyses are completed by the IceCube Collaboration.
Diffractive Processes at Next-to-Leading Order in the Dipole Picture
2023
Diffraktiiviset prosessit ovat korkean energian rajalla sensitiivisiä kohdehiukkasen gluonijakaumalle, mistä johtuen niiden avulla voidaan tutkia kohdetta kvanttiväridynamiikan epälineaarisessa alueessa. Näiden epälineaaristen ilmiöiden odotetaan johtavan gluonisaturaatioon, jota voidaan kuvata luontevasti värilasikondensaatiksi kutsutun efektiivisen kenttäteorian avulla. Vaikka saatavilla olevassa kokeellisessa datassa onkin vahvoja viitteitä gluonisaturaatiosta, yksiselitteistä merkkiä saturaatiosta ei ole havaittu. Tämän vuoksi on tärkeää parantaa saturaatiolle sensitiivisten prosessien teoreettista ymmärrystä, jotta pystytään löytämään selkeitä eroja kvanttiväridynamiikan lineaarisen ja…
LeptoGen-koodi
2021
LeptoGen is a software package for numerically solving (resonant) leptogenesis equations including full flavour coherence information for the Majorana neutrinos. The package is written in Wolfram Language and can be run in the Mathematica front end. (Tested in Mathematica 12.0.) For usage license, see the attachment.