6,194 research outputs found
Decays of the f0(1370) scalar glueball candidate in pp Central Exclusive Production (CEP) and in antiproton annihilations at rest
Decays into two charged pions of the f0(1370) are the main source of an
isolated structure localized between 1.2 and 1.5 GeV in the two charged pions
mass spectrum measured in pp Central Exclusive Production (CEP) at 200 GeV at
very low four momentum transfer ltl by the STAR experiment. These data confirm
in the two charged pions decay channel the existence of the f0(1370) as an
isolated well identified structure previously observed in K+K-, KsKs, 4 charged
pions, two charged and two neutral pions and 4 neutral pions decays measured in
antiproton annihilations at rest. The ensemble of these data point at a high
gluon content of the f0(1370). CEP interactions at higher energies favour
production of 0++ and 2++ mesons. Selection of events with lower ltl at both
proton vertices suppresses 2++ structures. LHC runs dedicated to pp CEP
measurements at low ltl could then provide a unique source of all the low
energy scalars. This would make it clear if and where scalar gluonium is
resident and the nature (composition in terms of quarks, antiquarks and gluons)
of f0(500), f0(980), f0(1370), f0(1500) and f0(1710).Comment: 8 pages, 5 figures, presented at QCD@Work-International Workshop on
QCD Theory and Experiment, 25-28 June 2018, Matera, Italy (to be published in
Proceedings). arXiv admin note: text overlap with arXiv:1809.0449
The contribution of NLO and LPM corrections to thermal dilepton emission in heavy ion collisions
Recently lots of efforts have been made to obtain the next to leading order
and Landau-Pomeranchuk-Migdal corrections to the thermal dilepton emission rate
in perturbative QCD. Here we apply these results to the plasma created in heavy
ion collisions and see wether these corrections improve the comparison between
theoretical calculations and experimental results for the invariant mass
dependence of the dilepton emission rate. In particular, we simulate the
quark-gluon plasma produced at RHIC and LHC using a 2+1-dimensional viscous
hydro model. We compare our results to STAR experiment and comment on the need
for a non-perturbative determination of the dilepton rate at low invariant
mass.Comment: 9 pages, 11 figure
Decays into {\pi}+{\pi}- of the f0(1370) scalar glueball candidate in pp central exclusive production experiments
The existence and properties of the f0(1370) scalar meson are rather well
established from data of antiproton annihilations at rest. However conflicting
results from Central Exclusive Production (CEP) experiments of the last
millennium and ignorance of data from antiproton annihilations at rest in H2
and D2 bubble chambers have generated doubts on the very existence of the
f0(1370). Properties of {\pi}+{\pi}- pairs produced in central exclusive
production (CEP) reactions observed in old data together with data collected in
the current decade at high energy colliders permit to show that {\pi}+{\pi}-
decays of the f0(1370) meson are directly observable as an isolated peak
between 1.1 and 1.6 GeV. Consequences of this observation and prospects for the
identification of the scalar glueball ground-state are discussed.Comment: 20 pages, 11 figure
The domestic stability pact in Italy: a rule for discipline?
The 1999-2006 versions of the Italian Domestic Stability Pact had many shortcomings and a modest impact with respect to the aim of aligning the fiscal behaviour of sub-national government units with the national commitments under the European Stability and Growth Pact. The Domestic Pact was revised in 2007 and 2008 to tighten the monitoring and sanctions framework and prevent some inefficient behaviour. However, some undesirable features still mar the new regime: no coordination exists between the Domestic Pact and the debt and tax constraints applied to local governments; a clear definition of the contribution of sub-national governments to aggregate compliance with the external rule is still lacking; flexibility has been introduced by means of an artificial reference budget balance; side effects on resource redistribution are ignored; and monitoring and sanctioning remain weak. Remedies for the above shortcomings can possibly be found in the domestic pacts of the other EMU countries. Most of all, the Domestic Pact should be adjusted to the specific characteristics of fiscal decentralization in Italy, where a large fiscal gap exists, revenue autonomy is constrained and a large share of the responsibility for spending is rigid and politically sensitive.Domestic Stability Pact, fiscal federalism
Economic integration and government size: a review of the empirical literature
This paper reviews the empirical literature concerning the impact of economic integration on the size and the composition of the public budget. From a theoretical perspective, a pessimistic view highlights the threat that economic integration constitutes to the action of the public sector. An optimistic view, instead, emphasizes the beneficial effects of integration in stimulating efficiency â enhancing public policies. Despite some well-established theoretical results, the empirical evidence on this topic is rather controversial. Some studies support the hypothesis that taxes and public spending may increase in order to compensate losers for the risks of a more open economic environment. Other studies support the opposite idea, that the public sector retrenches when having to face increasing mobility of the production factors. Yet, comparability of the wide empirical evidence on the topic is not straightforward and empirical regularities are hard to find.tax revenue, public spending, government size, trade openness, capital openness, economic integration, globalisation
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