175 research outputs found
Fulfillment of the strong bootstrap condition
The self-consistency of the assumption of Reggeized form of the production amplitudes in multi-Regge kinematics, which are used in the derivation of the BFKL equation, leads to strong bootstrap conditions. The fulfillment of these conditions opens the way to a rigorous proof of the BFKL equation in the next-to-leading approximation. The strong bootstrap condition for the kernel of the BFKL equation for the octet color state of two Reggeized gluons is one of these conditions. We show that it is satisfied in the next-to-leading approximation
On relativization of the Sommerfeld-Gamow-Sakharov factor
The Sommerfeld-Gamow-Sakharov factor is considered for the general case of
arbitrary masses and energies. It is shown that the scalar triangular one-loop
diagram gives the Coulomb singularity in radiative corrections at the
threshold. The singular part of the correction is factorized at the complete
Born cross section regardless of its partial wave decomposition. Different
approaches to generalize the factor are discussed.Comment: 9 pages, 4 figures; references and discussion are extende
The next-to-leading order forward jet vertex in the small-cone approximation
We consider within QCD collinear factorization the process p+p to jet + jet
+X, where two forward high- jets are produced with a large separation in
rapidity (Mueller-Navelet jets). In this case the (calculable) hard
part of the reaction receives large higher-order corrections , which can be accounted for in the BFKL approach. In particular,
we calculate in the next-to-leading order the impact factor (vertex) for the
production of a forward high- jet, in the approximation of small aperture
of the jet cone in the pseudorapidity-azimuthal angle plane. The final
expression for the vertex turns out to be simple and easy to implement in
numerical calculations.Comment: 32 pages, 4 figures; a few comments and one reference added; a few
inessential misprints removed; version to appear on JHE
Inclusive production of a pair of hadrons separated by a large interval of rapidity in proton collisions
We consider within QCD collinear factorization the inclusive process , where the pair of identified hadrons, , having large
transverse momenta is produced in high-energy proton-proton collisions. In
particular, we concentrate on the kinematics where the two identified hadrons
in the final state are separated by a large interval of rapidity . In
this case the (calculable) hard part of the reaction receives large higher
order corrections . We provide a theoretical input
for the resummation of such contributions with next-to-leading logarithmic
accuracy (NLA) in the BFKL approach. Specifically, we calculate in NLA the
vertex (impact-factor) for the inclusive production of the identified hadron.
This process has much in common with the widely discussed Mueller-Navelet jets
production and can be also used to access the BFKL dynamics at proton
colliders. Another application of the obtained identified-hadron vertex could
be the NLA BFKL description of inclusive forward hadron production in DIS.Comment: 29 pages, 9 figures; corrected few typos and added an acknowledgment;
version to be published on JHEP. arXiv admin note: substantial text overlap
with arXiv:1202.108
Hysteresis of Backflow Imprinted in Collimated Jets
We report two different types of backflow from jets by performing 2D special
relativistic hydrodynamical simulations. One is anti-parallel and
quasi-straight to the main jet (quasi-straight backflow), and the other is bent
path of the backflow (bent backflow). We find that the former appears when the
head advance speed is comparable to or higher than the local sound speed at the
hotspot while the latter appears when the head advance speed is slower than the
sound speed bat the hotspot. Bent backflow collides with the unshocked jet and
laterally squeezes the jet. At the same time, a pair of new oblique shocks are
formed at the tip of the jet and new bent fast backflows are generated via
these oblique shocks. The hysteresis of backflow collisions is thus imprinted
in the jet as a node and anti-node structure. This process also promotes
broadening of the jet cross sectional area and it also causes a decrease in the
head advance velocity. This hydrodynamic process may be tested by observations
of compact young jets.Comment: 9 pages, 5 figures, accepted for publication in ApJ
Heavy quark impact factor in kT-factorization
We present the calculation of the finite part of the heavy quark impact factor at next-to-leading logarithmic accuracy in a form suitable for phenomenological studies such as the calculation of the cross-section for single bottom quark production at the LHC within the kT-factorization scheme
The infrared structure of gauge theory amplitudes in the high-energy limit
We develop an approach to the high-energy limit of gauge theories based on the universal properties of their infrared singularities. Our main tool is the dipole formula, a compact ansatz for the all-order infrared singularity structure of scattering amplitudes of massless partons. By taking the high-energy limit, we show that the dipole formula implies Reggeization of infrared-singular contributions to the amplitude, at leading logarithmic accuracy, for the exchange of arbitrary color representations in the cross channel. We observe that the real part of the amplitude Reggeizes also at next-to-leading logarithmic order, and we compute the singular part of the two-loop Regge trajectory, which is universally expressed in terms of the cusp anomalous dimension. Our approach provides tools to study the high-energy limit beyond the boundaries of Regge factorization: thus we show that Reggeization generically breaks down at next-to-next-to-leading logarithmic accuracy, and provide a general expression for the leading Reggeization-breaking operator. Our approach applies to multiparticle amplitudes in multi-Regge kinematics, and it also implies new constraints on possible corrections to the dipole formula, based on the Regge limit
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