6,441 research outputs found
Polarised Drell-Yan at COMPASS-II
The study of Drell-Yan (DY) processes involving the collision of an unpolarised hadron beam on a polarised proton target can result in a fundamental improvement of our knowledge on the transverse-momentum–dependent (TMD)
parton distribution functions (PDFs) of hadron. A fundamental test of the factorization theorem in the
non-perturbative QCD can be performed as well, by verifying
the sign change of T-odd TMDs as they are accessed via
Semi-Inclusive Deep Inelastic Scattering (SIDIS) or
Drell-Yan process. The future polarised COMPASS Drell-Yan experiment is discussed in this context, the most important features are briefly reviewed, the sensitivity of the measurement is presented
Probing the deuteron structure at small NN distances by antiproton-deuteron annihilation
The production of pions by antiproton-deuteron annihilation at rest is
analyzed. Assuming the possible existence of two delta-isobars in a deuteron
some enhancement in the distribution over the invariant mass of two negative
charged pions is predicted.Comment: 12 pages, Latex and Postscrip
Broken space-time symmetries and mechanisms of rectification of ac fields by nonlinear (non)adiabatic response
We consider low-dimensional dynamical systems exposed to a heat bath and to
additional ac fields. The presence of these ac fields may lead to a breaking of
certain spatial or temporal symmetries which in turn cause nonzero averages of
relevant observables. Nonlinear (non)adiabatic response is employed to explain
the effect. We consider a case of a particle in a periodic potential as an
example and discuss the relevant symmetry breakings and the mechanisms of
rectification of the current in such a system.Comment: 11 pages, 10 figure
Photon waiting time distributions: a keyhole into dissipative quantum chaos
Open quantum systems can exhibit complex states, which classification and
quantification is still not well resolved. The Kerr-nonlinear cavity,
periodically modulated in time by coherent pumping of the intra-cavity photonic
mode, is one of the examples. Unraveling the corresponding Markovian master
equation into an ensemble of quantum trajectories and employing the recently
proposed calculation of quantum Lyapunov exponents [I.I. Yusipov {\it et al.},
Chaos {\bf 29}, 063130 (2019)], we identify `chaotic' and `regular' regimes
there. In particular, we show that chaotic regimes manifest an intermediate
power-law asymptotics in the distribution of photon waiting times. This
distribution can be retrieved by monitoring photon emission with a
single-photon detector, so that chaotic and regular states can be discriminated
without disturbing the intra-cavity dynamics.Comment: 7 pages, 5 figure
An evolution equation as the WKB correction in long-time asymptotics of Schrodinger dynamics
We consider 3d Schrodinger operator with long-range potential that has
short-range radial derivative. The long-time asymptotics of non-stationary
problem is studied and existence of modified wave operators is proved. It turns
out, the standard WKB correction should be replaced by the solution to certain
evolution equation.Comment: This is a preprint of an article whose final and definitive form has
been published in Comm. Partial Differential Equations, available online at
http://www.informaworld.co
- …