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Author Greynat, D.; de Rafael, E.; Vulvert, G.
Title Asymptotic behaviour of pion-pion total cross-sections Type Journal Article
Year 2014 Publication Journal of High Energy Physics Abbreviated Journal J. High Energy Phys.
Volume 03 Issue 3 Pages (down) 107 - 21pp
Keywords QCD Phenomenology; Phenomenological Models
Abstract We derive a sum rule which shows that the Froissart-Martin bound for the asymptotic behaviour of the pi pi total cross sections at high energies, if modulated by the Lukaszuk-Martin coefficient of the leading log(2)s behaviour, cannot be an optimal bound in QCD. We next compute the total cross sections for pi(+)pi(-), pi(+/-)pi(0) and pi(0)pi(0) scattering within the framework of the constituent chiral quark model (C chi QM) in the limit of a large number of colours N-c and discuss their asymptotic behaviours. The same pi pi cross sections are also discussed within the general framework of Large-N-c QCD and we show that it is possible to make an Ansatz for the isospin I = 1 and I = 0 spectrum which satisfy the Froissart-Martin bound with coefficients which, contrary to the Lukaszuk-Martin coefficient, are not singular in the chiral limit and have the correct Large-N-c counting. We finally propose a simple phenomenological model which matches the low energy behaviours of the sigma(total)(pi +/-pi 0)(s) cross section predicted by the CxQM with the high energy behaviour predicted by the Large-N-c Ansatz. The magnitude of these cross sections at very high energies is of the order of those observed for the pp and pp scattering total cross sections.
Address [Greynat, David] Univ Naples Federico II, Dipartimento Sci Fis, I-80126 Naples, Italy, Email: david.greynat@gmail.com;
Corporate Author Thesis
Publisher Springer Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1029-8479 ISBN Medium
Area Expedition Conference
Notes WOS:000333803000003 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 1747
Permanent link to this record
 
 
Author Qin, W.; Dai, L.Y.; Portoles, J.
Title Two and three pseudoscalar production in e(+)e(-) annihilation and their contributions to (g-2)(mu) Type Journal Article
Year 2021 Publication Journal of High Energy Physics Abbreviated Journal J. High Energy Phys.
Volume 03 Issue 3 Pages (down) 092 - 38pp
Keywords Phenomenological Models; QCD Phenomenology
Abstract A coherent study of e(+)e(-) annihilation into two (pi(+)pi(-), K+K-) and three (pi(+)pi(-)pi(0), pi(+)pi(-)eta) pseudoscalar meson production is carried out within the framework of resonance chiral theory in energy region E less than or similar to 2 GeV. The work of [L.Y. Dai, J. Portoles, and O. Shekhovtsova, Phys. Rev. D88 (2013) 056001] is revisited with the latest experimental data and a joint analysis of two pseudoscalar meson production. Hence, we evaluate the lowest order hadronic vacuum polarization contributions of those two and three pseudoscalar processes to the anomalous magnetic moment of the muon. We also estimate some higher-order additions led by the same hadronic vacuum polarization. Combined with the other contributions from the standard model, the theoretical prediction differs still by (21.6 +/- 7.4) x 10(-10) (2.9 sigma) from the experimental value.
Address [Qin, Wen; Dai, Ling-Yun] Hunan Univ, Sch Phys & Elect, Changsha 410082, Peoples R China, Email: wqin@hnu.edu.cn;
Corporate Author Thesis
Publisher Springer Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1029-8479 ISBN Medium
Area Expedition Conference
Notes WOS:000627781500001 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 4764
Permanent link to this record
 
 
Author Deak, M.
Title Estimation of saturation and coherence effects in the KGBJS equation – a non-linear CCFM equation Type Journal Article
Year 2013 Publication Journal of High Energy Physics Abbreviated Journal J. High Energy Phys.
Volume 07 Issue 7 Pages (down) 087 - 18pp
Keywords QCD Phenomenology
Abstract We solve the modified non-linear extension of the CCFM equation – KGBJS equation – numerically for certain initial conditions and compare the resulting dipole amplitudes with those obtained front solving the original CCFM equation and the BFKL and BK equations for the same initial conditions. We improve the low transversal momentum behaviour of the KGBJS equation by a small modification.
Address [Deak, M.] Univ Santiago de Compostela, Fac Fis, Dept Fis Particulas, Santiago De Compostela 15706, Spain, Email: michal.deak@ific.uv.es
Corporate Author Thesis
Publisher Springer Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1029-8479 ISBN Medium
Area Expedition Conference
Notes WOS:000323202600087 Approved no
Is ISI yes International Collaboration no
Call Number IFIC @ pastor @ Serial 1636
Permanent link to this record
 
 
Author Deak, M.; Kutak, K.
Title Kinematical constraint effects in the evolution equations based on angular ordering Type Journal Article
Year 2015 Publication Journal of High Energy Physics Abbreviated Journal J. High Energy Phys.
Volume 05 Issue 5 Pages (down) 068 - 13pp
Keywords QCD Phenomenology; Deep Inelastic Scattering (Phenomenology)
Abstract We study effects of imposing various forms of the kinematical constraint on the full form of the CCFM equation and its non-linear extension. We find, that imposing the constraint in its complete form modifies significantly the shape of gluon density as compared to forms of the constraint used in numerical calculations and phenomenological applications. In particular the resulting gluon density is suppressed for large values of the hard scale related parameter and k(T) of gluon. This result might be important in description of jet correlations at Large Hadron Collider within the CCFM approach.
Address [Deak, Michal] Univ Valencia, CSIC, IFIC, E-46071 Valencia, Spain, Email: michal.deak@ific.uv.es;
Corporate Author Thesis
Publisher Springer Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1029-8479 ISBN Medium
Area Expedition Conference
Notes WOS:000356951500006 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 2290
Permanent link to this record
 
 
Author Bordes, J.; Dominguez, C.A.; Moodley, P.; Peñarrocha, J.; Schilcher, K.
Title Chiral corrections to the SU(2) x SU(2) Gell-Mann-Oakes-Renner relation Type Journal Article
Year 2010 Publication Journal of High Energy Physics Abbreviated Journal J. High Energy Phys.
Volume 05 Issue 5 Pages (down) 064 - 16pp
Keywords QCD Phenomenology
Abstract The next to leading order chiral corrections to the SU(2) x SU(2) Gell-Mann-Oakes- Renner (GMOR) relation are obtained using the pseudoscalar correlator to five-loop order in perturbative QCD, together with new finite energy sum rules (FESR) incorporating polynomial, Legendre type, integration kernels. The purpose of these kernels is to suppress hadronic contributions in the region where they are least known. This reduces considerably the systematic uncertainties arising from the lack of direct experimental information on the hadronic resonance spectral function. Three different methods are used to compute the FESR contour integral in the complex energy (squared) s-plane, i.e. Fixed Order Perturbation Theory, Contour Improved Perturbation Theory, and a fixed renormalization scale scheme. We obtain for the corrections to the GMOR relation, delta(pi), the value delta(pi) = (6.2 +/- 1.6)%. This result is substantially more accurate than previous determinations based on QCD sum rules; it is also more reliable as it is basically free of systematic uncertainties. It implies a light quark condensate < 0 vertical bar(u) over baru vertical bar 0 > similar or equal to < 0 vertical bar(d) over bard vertical bar 0 > < 0 vertical bar(q) over barq vertical bar 0 >vertical bar(2GeV) = (-267 +/- 5MeV)(3). As a byproduct, the chiral perturbation theory (unphysical) low energy constant H-2(r) is predicted to be H-2(r)(nu(X) = M-p) = -(5.1 +/- 1.8) x10(-3), or H-2(r) (nu(X) = M-eta) = -(5.7 +/- 2.0) x10(-3).
Address [Bordes, J.; Penarrocha, J.] Univ Valencia, Dept Fis Teor, CSICE, E-46100 Burjassot, Spain, Email: bordes@uv.es
Corporate Author Thesis
Publisher Springer Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1126-6708 ISBN Medium
Area Expedition Conference
Notes ISI:000278250000044 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ elepoucu @ Serial 434
Permanent link to this record
 
 
Author Coppola, M.; Gomez Dumm, D.; Noguera, S.; Scoccola, N.N.
Title Magnetic field driven enhancement of the weak decay width of charged pions Type Journal Article
Year 2020 Publication Journal of High Energy Physics Abbreviated Journal J. High Energy Phys.
Volume 09 Issue 9 Pages (down) 058 - 19pp
Keywords QCD Phenomenology
Abstract We study the effect of a uniform magnetic field B on the decays pi- > l- nu_l bar, where l(-)=e(-), μ(-), carrying out a general analysis that includes four pi (-) decay constants. Taking the values of these constants from a chiral effective Nambu-Jona-Lasinio (NJL) model, it is seen that the total decay rate gets strongly increased with respect to the B = 0 case, with an enhancement factor ranging from similar to 10 for eB = 0.1 GeV2 up to similar to 10(3) for eB = 1 GeV2. The ratio between electronic and muonic decays gets also enhanced, reaching a value of about 1 : 2 for eB = 1 GeV2. In addition, we find that for large B the angular distribution of outgoing antineutrinos shows a significant suppression in the direction of the magnetic field.
Address [Coppola, Maximo; Scoccola, Norberto N.] Consejo Nacl Invest Cient & Tecn, Rivadavia 1917, RA-1033 Buenos Aires, DF, Argentina, Email: coppola@tandar.cnea.gov.ar;
Corporate Author Thesis
Publisher Springer Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1029-8479 ISBN Medium
Area Expedition Conference
Notes WOS:000570908100001 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 4534
Permanent link to this record
 
 
Author de Florian, D.; Sborlini, G.F.R.; Rodrigo, G.
Title Two-loop QED corrections to the Altarelli-Parisi splitting functions Type Journal Article
Year 2016 Publication Journal of High Energy Physics Abbreviated Journal J. High Energy Phys.
Volume 10 Issue 10 Pages (down) 056 - 16pp
Keywords NLO Computations; QCD Phenomenology
Abstract We compute the two-loop QED corrections to the Altarelli-Parisi (AP) splitting functions by using a deconstructive algorithmic Abelianization of the well-known NLO QCD corrections. We present explicit results for the full set of splitting kernels in a basis that includes the leptonic distribution functions that, starting from this order in the QED coupling, couple to the partonic densities. Finally, we perform a phenomenological analysis of the impact of these corrections in the splitting functions.
Address [de Florian, Daniel] UNSAM, ICAS, Campus Miguelete,25 Mayo & Francia, RA-1650 Buenos Aires, DF, Argentina, Email: deflo@unsam.edu.ar;
Corporate Author Thesis
Publisher Springer Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1029-8479 ISBN Medium
Area Expedition Conference
Notes WOS:000386669900007 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 2863
Permanent link to this record
 
 
Author Ferrario, P.; Rodrigo, G.
Title Heavy colored resonances in t(t)over-bar + jet at the LHC Type Journal Article
Year 2010 Publication Journal of High Energy Physics Abbreviated Journal J. High Energy Phys.
Volume 02 Issue 2 Pages (down) 051 - 13pp
Keywords QCD Phenomenology
Abstract The LHC is the perfect environment for the study of new physics in the top quark sector. We study the possibility of detecting signals of heavy color-octet vector resonances, through the charge asymmetry, in t (t) over bar + jet events. Besides contributions with the t (t) over bar pair in a color-singlet state, the asymmetry gets also contributions which are proportional to the color factor f(abc)(2). This process is particularly interesting for extra-dimensional models, where the inclusive charge asymmetry generated by Kaluza-Klein excitations of the gluon vanishes at the tree level. We find that the statistical significance for the measurement of such an asymmetry is sizable for different values of the coupling constants and already at low energies.
Address [Ferrario, Paola; Rodrigo, German] UVEG, Consejo Super Invest Cient, Inst Fis Corpuscular, E-46071 Valencia, Spain, Email: paola.ferrario@ific.uv.es
Corporate Author Thesis
Publisher Springer Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1126-6708 ISBN Medium
Area Expedition Conference
Notes ISI:000275223100051 Approved no
Is ISI yes International Collaboration no
Call Number IFIC @ elepoucu @ Serial 483
Permanent link to this record
 
 
Author Kleiss, R.H.P.; Malamos, I.; Papadopoulos, C.G.; Verheyen, R.
Title Counting to one: reducibility of one- and two-loop amplitudes at the integrand level Type Journal Article
Year 2012 Publication Journal of High Energy Physics Abbreviated Journal J. High Energy Phys.
Volume 12 Issue 12 Pages (down) 038 - 24pp
Keywords QCD Phenomenology; NLO Computations
Abstract Calculation of amplitudes in perturbative quantum field theory involve large loop integrals. The complexity of those integrals, in combination with the large number of Feynman diagrams, make the calculations very difficult. Reduction methods proved to be very helpful, lowering the number of integrals that need to be actually calculated. Especially reduction at the integrand level improves the speed and set-up of these calculations. In this article we demonstrate, by counting the numbers of tensor structures and independent coefficients, how to write such relations at the integrand level for one-and two-loop amplitudes. We clarify their connection to the so-called spurious terms at one loop and discuss their structure in the two-loop case. This method is also applicable to higher loops, and the results obtained apply to both planar and non-planar diagrams.
Address [Kleiss, Ronald H. P.; Verheyen, Rob] Radboud Univ Nijmegen, NL-6525 ED Nijmegen, Netherlands, Email: R.Kleiss@science.ru.nl;
Corporate Author Thesis
Publisher Springer Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1126-6708 ISBN Medium
Area Expedition Conference
Notes WOS:000313123800038 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 1346
Permanent link to this record
 
 
Author Bierenbaum, I.; Buchta, S.; Draggiotis, P.; Malamos, I.; Rodrigo, G.
Title Tree-loop duality relation beyond single poles Type Journal Article
Year 2013 Publication Journal of High Energy Physics Abbreviated Journal J. High Energy Phys.
Volume 03 Issue 3 Pages (down) 025 - 24pp
Keywords QCD Phenomenology; NLO Computations
Abstract We develop the Tree-Loop Duality Relation for two- and three-loop integrals with multiple identical propagators (multiple poles). This is the extension of the Duality Relation for single poles and multi-loop integrals derived in previous publications. We prove a generalization of the formula for single poles to multiple poles and we develop a strategy for dealing with higher-order pole integrals by reducing them to single pole integrals using Integration By Parts.
Address Univ Hamburg, Inst Theoret Phys 2, D-22761 Hamburg, Germany, Email: isabella.bierenbaum@desy.de;
Corporate Author Thesis
Publisher Springer Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1029-8479 ISBN Medium
Area Expedition Conference
Notes WOS:000317521200025 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 1418
Permanent link to this record