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G. Morpurgo

Publications and source records attributed to G. Morpurgo.

11 recordsLinked to original sources
arXiv2011

Some remarks on a paper by G.-S. Yang and H.-C.Kim: Mass splitting of SU(3) baryons within a chiral soliton model

In a recent paper Yang and Kim discuss the lowest baryon mass formulas using a chiral soliton model. However, contrary to their assertion, their result is not equivalent to a generalized Gell Mann-Okubo mass formula derived (G.Morpurgo 1992) using only general properties of QCD (The General parameterization method). The reason for the non equivalence is that the generalized mass formula include all the main terms that break flavor at second order, whereas the Authors above do not go beyond first order flavor breaking (and should therefore find the usual Gell Mann Okubo formula). That is is not so, due to some inconsistencies. Below we confine to the part of the Yang-Kim paper dealing with the mass formula. We will not consider the other items of their paper.

hep-ph↗
arXiv2010

The general QCD parametrization and the hierarchy of its parameters. (Why some simple models of hadrons work so well)

After summarizing the basic points of the general QCD parametrization (GP) we discuss systematically its applications to the properties of the lowest families of baryons and mesons. We show how the hierarchy of the parameters in the GP emerges clearly in the properties of hadrons. Among other things, it explains why simple models can work reasonably well and clarifies the relationship between current and constituent quarks. More details on the hadron properties discussed with the GP appear from the list of secrions at the beginning of the paper.

hep-ph↗
arXiv2007

The baryon octet magnetic moments to all orders in flavor breaking; an application to the problem of the strangeness in the nucleon

Using the general QCD parametrization (GP) we display the magnetic moments of the octet baryons including all flavor breaking terms to any order. The hierarchy of the GP parameters allows to estimate a parameter $g_{0}$ related to the quark loops contribution of the proton magnetic moment; its order of magnitude is predicted to be inside a comparatively small interval including the value given recently by Leinweber et al. by a lattice QCD calculation

hep-ph↗
arXiv2003

The CERN Detector Safety System for the LHC Experiments

The Detector Safety System (DSS), currently being developed at CERN under the auspices of the Joint Controls Project (JCOP), will be responsible for assuring the protection of equipment for the four LHC experiments. Thus, the DSS will require a high degree of both availability and reliability. After evaluation of various possible solutions, a prototype is being built based on a redundant Siemens PLC front-end, to which the safety-critical part of the DSS task is delegated. This is then supervised by a PVSS SCADA system via an OPC server. The PLC front-end is capable of running autonomously and of automatically taking predefined protective actions whenever required. The supervisory layer provides the operator with a status display and with limited online reconfiguration capabilities. Configuration of the code running in the PLCs will be completely data driven via the contents of a "Configuration Database". Thus, the DSS can easily adapt to the different and constantly evolving requirements of the LHC experiments during their construction, commissioning and exploitation phases.

hep-ex↗
arXiv2003

Chiral QCD, General QCD Parameterization and Constituent Quark Models

Several recent papers -using effective QCD chiral Lagrangians- reproduced results obtained with the general QCD parameterization (GP). These include the baryon 8+10 mass formula, the octet magnetic moments and the coincidental nature of the "perfect" -3/2 ratio between the magnetic moments of p and n. Although we anticipated that the GP covers the case of chiral treatments, the above results explicitly exemplify this fact. Also we show by the GP that -in any model or theory (chiral or non chiral) reproducing the results of exact QCD- the Franklin (Coleman Glashow) sum rule for the octet magnetic moments must be violated.

hep-ph↗
arXiv2001

A relation between the charge radii of π^{+},\K^{+},K^{o} derived by the general QCD parametrization

We derive,using the general QCD parametrization,the approximate relation r^{2}(π^{+}) - r^{2}(K^(+)) approximately equal to -r^{2}(K^(o), where the r's are the charge radii.The relation is satisfied but the experimental errors are still sizeable.The derivation is similar to (but even simpler than) that for r^{2}(p) -r^{2}(n) approximately equal to r^{2}(Δ)[Phys.Lett.B 448,107 (1999)].

hep-ph↗
arXiv2000

The general QCD parametrization and the 1/N(c) expansion: A comparison

A comparison is presented of the two methods mentioned in the title for treating hadron properties in QCD.While the general parametrization is derived exactly from real QCD,the equivalence of the large N(c) description to real QCD with 3 colors,is questionable.The reason why in some cases the large N(c) method approximately works (while in others does not) is clarified.

hep-ph↗
arXiv2000

On the miracle of the Coleman-Glashow and other baryon mass formulas

Due to a new measurement of the Xi(0) mass,the Coleman-Glashow formula for the baryon octet e.m. masses (derived using unbroken SU(3) is satisfied to an extraordinary level of precision.The same unexpected precision exists for the Gell-Mann Okubo formula and for its octet-decuplet extension (G.Morpurgo,Phys.Rev.Lett. 68(1992)139).We show that the old question "why do they work so well?" is now answered by the general parameterization method.

hep-ph↗