Speaker
Antoni Szczurek
(Institute of Nuclear Physics)
Description
We calculate distribution of Higgs boson in rapidity and transverse
momentum within $k_t$-factorization with different unintegrated
gluon distribution functions from the literature (Kimber-Martin-Ryskin,
Jung-Salam, Kutak-Stasto, Kwiecinski CCFM, Ivanov-Nikolaev)
with leading order and next-to-leading order precision and with off-shell
matrix elements.
Special attention is devoted to the Kimber-Martin-Ryskin distribution
which is known to describe well gauge boson (W and Z) production,
Drell-Yan processes and heavy quark production.
We discuss and quantify contributions from different regions of
incoming gluon transverse momenta dividing the space into hard
and soft regions. We discuss how these regions may be roughly related
to fixed-order LO, NLO and NNLO calculations.
We include also the decay of the Higgs boson into photons and compare
results with recent preliminary data of the ATLAS Collaboration
for the Higgs boson transverse momentum and rapidity distributions.
The lowest order $k_t$-factorization contribution gives similar shape
for Higgs boson transverse momentum as the experimental one but underpredicts the new ATLAS
data. We discuss that the lowest-order $k_t$-factorization result does not
include e.g. NLO collinear-factorization contributions which are known
to be large. We show $k_t$-factorization NLO contributions ($g g \to H g$)
for different UGDFs. For completeness we show also contribution
of $WW$ fusion.
In addition, we show distributions in azimuthal angle between photons
and distributions in two-dimensional space of $p_{1t} x p_{2t}$
of transverse momenta of photons.
M. Luszczak, A. Szczurek, a paper in preparation.
Authors
Antoni Szczurek
(Institute of Nuclear Physics)
Marta Luszczak
(University of Rzeszow)
