58 research outputs found
Collectivity in pp from resummed interference effects?
Azimuthal asymmetries in the soft transverse momentum spectra of
hadronic collisions can result as a consequence of quantum interference and
color flow which translates spatial anisotropies into momentum anisotropies via
multipole radiation patterns. Here, we analyze to what extent these effects
result in signal strengths that can persist in higher
order cumulants. In a simple model of soft multi-particle production
with quantum interference effects in which particles are emitted from
sources and in which interference contributions appear naturally ordered in
inverse powers of the adjoint color trace, , we provide the first
resummed calculation of all powers of . This allows one to
determine all higher order flow cumulants with the same
parametric accuracy. For a phenomenologically relevant range of sources
emitting particles, we find that the even flow coefficients decrease very mildly with increasing cumulants. This provides a
proof of principle that non-vanishing higher order cumulants can persist in systems that exhibit neither final state interactions
nor phenomena related to high (saturated) initial parton densities.Comment: 8 pages, 1 Fi
Hard four-jet production in pA collisions
In a suitably chosen back-to-back kinematics, four-jet production in hadronic
collisions is known to be dominated by contributions from two independent
partonic scattering processes, thus giving experimental access to the structure
of generalized two-parton distributions 2GPDs. Here, we show that a combined
measurement of the double hard four-jet cross section in proton-proton and
proton-nucleus collisions will allow one to disentangle different sources of
two-parton correlations in the proton, that cannot be disentangled with 4-jet
measurements in proton-proton collisions alone. To this end, we analyze in
detail the structure of 2GPDs in the nucleus (A), we calculate in the
independent nucleon approximation all contributions to the double hard four-jet
cross section in pA, and we determine corrections arising from the nuclear
dependence of single parton distribution functions. We then outline an
experimental strategy for determining the longitudinal two-parton correlations
in the proton.Comment: 12 pages, 4 figures, revised version v2 to be published in EPJC,
argument in section 5 improve
Parton Hadron Duality in nonleptonic B hadron decays
Assuming so called global duality we argue that it is very likely that local
duality needed to obtain results for the hadronic width of heavy meson decays
within the expansion holds. Hence, if the discrepancy between
experiment and the theory concerning charm counting, the semileptonic branching
fraction and the lifetimes of hadrons persist, it may be taken as a hint at
some qualitatively new effect in (nonperturbative) QCD or even as a new
physics.Comment: Some thanks are adde
Regge asymptotics and color suppressed heavy meson decays
We discuss a possible generation of color suppressed B-decays amplitudes
through a soft final state interaction. As a typical example, we consider in
detail the decay (and also ). We show that in the approximation of the
two particle unitarity and at zero order in this process can be
related to the weak decay followed by
the strong charge exchange scattering in the Regge kinematics. We estimate the
amplitude of this process using the light cone QCD sum rule technique and find
that it is supppressed as a power of in comparison to the amplitude
generated by the effective non-leptonic Hamiltonian, but remains important for
the physical value of .Comment: 14 pages,Latex,no figure
On the Determination of from Inclusive Semileptonic Decay Spectra
We propose a model independent method to determine from the energy
spectrum of the charged lepton in inclusive semileptonic decays. The method
includes perturbative QCD corrections as well as nonperturbative ones.Comment: LaTeX, 19 pages, 8 figures appended after \end{document} as
uu-encoded and compressed .eps files, uses epsf, Technion-PH-94/9,
CERN-TH.7308/9
Proton lifetime, Yukawa couplings and dynamical SUSY breaking in SU(5) GUT
We study the influence of messenger Yukawa couplings and top, bottom and
Yukawa couplings on the proton lifetime in SU(5) Supersymmetric GUT with
dynamical supersymmetry breaking mechanism due to Dine and Nelson.Comment: 7 pages latex file, 6 ps figures include
Calculation of 1/m^3 terms in the total semileptonic width of D mesons.
We calculate the 1/ corrections in the inclusive semileptonic widths
of mesons. We show that these are due to the novel penguin type operators
that appear at this level in the transition operator. Taking into account the
nonperturbative corrections leads to the predicted value of the semileptonic
width significantly lower than the experimental value. The worsen the
situation or at the very least, within uncertainty, give small contribution. We
indicate possible ways out. It seems most probable that violations of duality
are noticeable in the energy range characteristic to the inclusive decays in
the charm family. Theoretically these deviations are related to divergence of
the high-order terms in the power expansion in the inverse heavy quark mass.Comment: Final version accepted for publication in Physical Review D (19
pages, 5 figures appended as two PS files at the end of the LATEX file
Annihilation, Rescattering, and CP Asymmetries in B Meson Decays
A number of meson decays may proceed only through participation of the
spectator quark, whether through amplitudes proportional to or via
rescattering from other less-suppressed amplitudes. An expected hierarchy of
amplitudes in the absence of rescattering will be violated by rescattering
corrections. Such violations could point the way toward channels in which
final-state interactions could be important. Cases in which final state phases
can lead to large CP asymmetries are pointed out.Comment: 9 page
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