From ADONE's multi-hadron production to the $J/\Psi$ discovery
The physics at Frascati in the years 60's - 70's is reviewed together with the $J/\Psi$ discovery.
hep-ph↗
arXiv subjects
Mario Greco
Publications and source records attributed to Mario Greco.
Muon Collider Physics Summary
The perspective of designing muon colliders with high energy and luminosity, which is being investigated by the International Muon Collider Collaboration, has triggered a growing interest in their physics reach. We present a concise summary of the muon colliders potential to explore new physics, leveraging on the unique possibility of combining high available energy with very precise measurements.
hep-ph↗
The physics case of a 3 TeV muon collider stage
In the path towards a muon collider with center of mass energy of 10 TeV or more, a stage at 3 TeV emerges as an appealing option. Reviewing the physics potential of such muon collider is the main purpose of this document. In order to outline the progression of the physics performances across the stages, a few sensitivity projections for higher energy are also presented. There are many opportunities for probing new physics at a 3 TeV muon collider. Some of them are in common with the extensively documented physics case of the CLIC 3 TeV energy stage, and include measuring the Higgs trilinear coupling and testing the possible composite nature of the Higgs boson and of the top quark at the 20 TeV scale. Other opportunities are unique of a 3 TeV muon collider, and stem from the fact that muons are collided rather than electrons. This is exemplified by studying the potential to explore the microscopic origin of the current $g$-2 and $B$-physics anomalies, which are both related with muons.
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Bruno Touschek and the physics at Frascati at the time of AdA and ADONE
The physics at Frascati in the years 60's - 70's is reviewed together with the role played by Bruno Touschek
physics.hist-ph↗
Higgs and BSM Physics at the future Muon Collider
We describe recent work on the physics of the Higgs boson at future muon colliders. Starting from the low energy muon collider at the Higgs boson pole we extend our discussion to the multi-TeV muon collider and outline the physics case for such machines about the properties of the Higgs boson and physics beyond the Standard Model that can be possibly discovered.
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ISR corrections to associated $HZ$ production at future Higgs factories
We evaluate the QED corrections due to initial state radiation (ISR) to associated Higgs boson production in electron-positron ($e^+ e^-$) annihilation at typical energies of interest for the measurement of the Higgs properties at future $e^+ e^-$ colliders, such as CEPC and FCC-ee. We apply the QED Structure Function approach to the four-fermion production process $e^+ e^- \to \mu^+ \mu^- b \bar b$, including both signal and background contributions. We emphasize the relevance of the ISR corrections particularly near threshold and show that finite third order collinear contributions are mandatory to meet the expected experimental accuracy. We analyze in turn the r\^ole played by a full four-fermion calculation and beam energy spread in precision calculations for Higgs physics at future $e^+ e^-$ colliders.
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Remembering Guido Altarelli
In memory of Guido Altarelli I present my personal recollections of the early times and his major role played in the development of QCD.
physics.hist-ph↗
ISR effects for resonant Higgs production at future lepton colliders
We study the effects of the initial state radiation on the $s$-channel Higgs boson resonant production at $\mu^+\mu^-$ and $e^+e^-$ colliders by convoluting with the beam energy spread profile of the collider and the Breit-Wigner resonance profile of the signal. We assess their impact on both the Higgs signal and SM backgrounds for the leading decay channels $h\rightarrow b\bar b,\ WW^*$. Our study improves the existing analyses of the proposed future resonant Higgs factories and provides further guidance for the accelerator designs with respect to the physical goals.
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On the study of the Higgs properties at a muon collider
The discovery of the Higgs particle at 125 GeV is demanding a detailed knowledge of the properties of this fundamental component of the Standard Model. To that aim various proposals of electron and muon colliders have been put forward for precision studies of the partial widths of the various decay channels. It is shown that in the case of a Higgs factory through a muon collider, sizeable radiative effects - of order of 50% - must be carefully taken into account for a precise measurement of the leptonic and total widths of the Higgs particle. Similar effects do not apply in the case of Higgs production in electron-positron colliders.
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D^* production from e^+e^- to ep collisions in NLO QCD
Fragmentation functions for D mesons, based on the convolution of a perturbative part, related to the heavy quark perturbative showering, and a non-perturbative model for its hadronization into the meson, are used to describe D^* production in e^+e^- and ep collisions. The non-perturbative part is determined by fitting the e^+e^- data taken by ARGUS and OPAL at 10.6 and 91.2 GeV respectively. When fitting with a non perturbative Peterson fragmentation function and using next-to-leading evolution for the perturbative part, we find an epsilon parameter sensibly different from the one commonly used, which is instead found with a leading order fit. The use of this new value is shown to increase considerably the cross section for D^* production at HERA, suggesting a possible reconciliation between the next-to-leading order theoretical predictions and the experimental data.
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Associated J/psi + gamma Photoproduction as a Probe of the Colour-Octet Mechanism
The associated production of a J/psi and a photon in photon-hadron collisions is considered, and shown to be a good probe of the presence of colour-octet mediated channels in quarkonia production, as predicted by the factorization approach within NRQCD. Total and differential cross sections for photoproduction at fixed target experiments and at HERA are presented. Associated J/psi + gamma production at hadron colliders is briefly discussed.
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Charm Production via Fragmentation
The next-to-leading open charm production in $γp$ collisions is calculated within the Perturbative Fragmentation Functions formalism, to allow resummation of $\as\log(\pt^2/m^2)$ terms. In the large $\pt$ region $(\pt > m)$ the result is consistent with the fixed order NLO calculation, small discrepancies being found for very large $\pt$ and at the edge of phase space. The two approaches differ in the definition and the relative contribution of the direct and resolved terms, but essentially agree on their sum. The resummation is found to lead to a reduced sensitivity to the choice of the renormalization/factorization scale.
hep-ph↗
Light mesons production at the Tevatron to next-to-leading order
Inclusive production of light mesons ($π^0$, $η$, $π^{\pm}$, $K^{\pm}$ ) at the Tevatron is considered in QCD to next-to-leading order in the formalism of fragmentation functions. We present various distributions of phenomenological interest, along with a new set of $K$ mesons fragmentation functions.
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