arXiv subjects
F. Maltoni
Publications and source records attributed to F. Maltoni.
Associated production of Higgs and single top at hadron colliders
We study the production of the Higgs boson in association with a single top quark at hadron colliders. The cross sections for the three production processes (t-channel, s-channel, and W-associated) at both the Tevatron and the LHC are presented. We investigate the possibility of detecting a signal for the largest of these processes, the t-channel process at the LHC, via the Higgs decay into b b-bar. The QCD backgrounds are large and difficult to curb, hindering the extraction of the signal. Extensions of our analysis to the production of supersymmetric Higgs bosons are also addressed. The cross section is enhanced for large values of tangent beta, increasing the prospects for extracting a signal.
W Boson Production with Associated Jets at Large Rapidities
We analyse W boson production at hadron colliders in association with one or two jets, both with the exact kinematics and in the high-energy limit. We argue that the configurations that are kinematically favoured tend to have the W boson forward in rapidity. Thus W boson production in association with jets lends itself naturally to extensions to the high-energy limit, which we examine both at leading order and by resumming higher-order corrections through the BFKL theory.
Upper bound on the scale of Majorana-neutrino mass generation
We derive a model-independent upper bound on the scale of Majorana-neutrino mass generation. The upper bound is $4πv^2/\sqrt 3 m_ν$, where $v \simeq 246$ GeV is the weak scale and $m_ν$ is the Majorana neutrino mass. For neutrino masses implied by neutrino oscillation experiments, all but one of these bounds are less than the Planck scale, and they are all within a few orders of magnitude of the grand-unification scale.
Non-trivial Behaviour of the Scattering Amplitude of Contact-interacting Anyons
It is shown that the scattering amplitude for contact-interacting anyons does exhibit a genuine non-perturbative sector. This means that the corresponding perturbative field theoretical formulation, based on the {\it 2+1} non-relativistic Chern-Simons gauge model coupled to self-interacting complex scalar field, is not generally able to reproduce, order by order in perturbation theory, the exact result. It is proven that the full agreement between the exact scattering amplitude and the resummation of the perturbative expansion of the renormalized 1PI amplitude actually occurs only for some continuous sub-family of self-adjoint extensions of the quantum Hamiltonians, which entail the absence of bound states. A comparison with previously obtained results is carefully worked out.
Colour Octet effects in Quarkonium Physics
The importance of including colour octet contributions in describing decay and production of quarkonium states is briefly discussed for two cases : the radiative decays of the $Υ$ and the production of $J/ψ$ in the inclusive $B$ decays. It is shown how information on the non-perturbative matrix elements can be obtained by comparing the theoretical expressions computed at next-to-leading order in $α_s$ with the experimental data.
QCD analysis of inclusive B decay into charmonium
We compute the decay rates and $H$-energy distributions of $B$ mesons into the final state $H+X$, where $H$ can be any one of the $S$-wave or $P$-wave charmonia, at next-to-leading order in the strong coupling. We find that a significant fraction of the observed $J/ψ$, $ψ'$ and $χ_c$ must be produced through $c\bar{c}$ pairs in a colour octet state and should therefore be accompanied by more than one light hadron. At the same time we obtain stringent constraints on some of the long-distance parameters for colour octet production.
NLO Production and Decay of Quarkonium
We present a calculation of next-to-leading-order (NLO) QCD corrections to total hadronic production cross sections and to light-hadron-decay rates of heavy quarkonium states. Both colour-singlet and colour-octet contributions are included. We discuss in detail the use of covariant projectors in dimensional regularization, the structure of soft-gluon emission and the overall finiteness of radiative corrections. We compare our approach with the NLO version of the threshold-expansion technique recently introduced by Braaten and Chen. Most of the results presented here are new. Others represent the first independent reevaluation of calculations already known in the literature. In this case a comparison with previous findings is reported.
Quarkonium Photoproduction at Next-to-leading Order
We present the calculation of O(as^2 aem) corrections to heavy-quarkonium total photoproduction cross-sections. Results are given for the colour-octet component of S and P waves. The calculation is performed using covariant projectors in dimensional regularization. A phenomenological study of the results, including a discussion of the high-energy behaviour of the cross sections, is presented. For gamma-p energies up to few hundred GeV the NLO corrections significantly reduce the scale dependence of the production rates relative to the Born-level results. Large small-x corrections arise at higher energies, making the predictions strongly dependent on the shape of the gluon density and on the choice of factorization scale.
Anomaly and Thermodynamics for 2D Spinors in the Aharonov--Bohm Gauge Field
The axial anomaly is computed for Euclidean Dirac fermions on the plane. The dependence upon the self-adjoint extensions of the Dirac operator is investigated and its relevance concerning the second virial coefficient of the anyon gas is discussed.