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The production of D(*+), D(0), D(+), D(s)(+) and Lambda(+)(c) charm hadrons and their antiparticles in ep scattering at HERA was measured with the ZEUS detector using an integrated luminosity of 79 pb(-1). The measurement has been performed in the photoproduction regime with the exchanged-photon virtuality Q(2) < 1 GeV(2) and for photon-proton centre-of-mass energies in the range 130 < W < 300 GeV. The charm hadrons were reconstructed in the range of transverse momentum PT (D, A,) > 3.8 GeV and pseudorapidity vertical bar eta(D, Lambda(c))vertical bar < 1.6. The production cross sections were used to determine the ratio of neutral and charged D-meson production rates, R(u/d), the strangeness-suppression factor, gamma(s), and the fraction of charged D mesons produced in a vector state, P(v)(d). The measured R(u/d) and gamma(s), values agree with those obtained in deep inelastic scattering and in e(+)e(-) annihilations. The measured P(v)(d) value is smaller than, but consistent with, the previous measurements. The fractions of c quarks hadronising as a particular charm hadron, f(c -> D, Lambda(c)), were derived in the given kinematic range. The measured open-charm fragmentation fractions are consistent with previous results, although the measured f(c -> D(*+)) is smaller and f (c -> Lambda(+)(c)) is larger than those obtained in e(+)e(-) annihilations. These results generally support the hypothesis that fragmentation proceeds independently of the hard sub-process.
The production of D(*+), D(0), D(+), D(s)(+) and Lambda(+)(c) charm hadrons and their antiparticles in ep scattering at HERA was measured with the ZEUS detector using an integrated luminosity of 79 pb(-1). The measurement has been performed in the photoproduction regime with the exchanged-photon virtuality Q(2) < 1 GeV(2) and for photon-proton centre-of-mass energies in the range 130 < W < 300 GeV. The charm hadrons were reconstructed in the range of transverse momentum PT (D, A,) > 3.8 GeV and pseudorapidity vertical bar eta(D, Lambda(c))vertical bar < 1.6. The production cross sections were used to determine the ratio of neutral and charged D-meson production rates, R(u/d), the strangeness-suppression factor, gamma(s), and the fraction of charged D mesons produced in a vector state, P(v)(d). The measured R(u/d) and gamma(s), values agree with those obtained in deep inelastic scattering and in e(+)e(-) annihilations. The measured P(v)(d) value is smaller than, but consistent with, the previous measurements. The fractions of c quarks hadronising as a particular charm hadron, f(c -> D, Lambda(c)), were derived in the given kinematic range. The measured open-charm fragmentation fractions are consistent with previous results, although the measured f(c -> D(*+)) is smaller and f (c -> Lambda(+)(c)) is larger than those obtained in e(+)e(-) annihilations. These results generally support the hypothesis that fragmentation proceeds independently of the hard sub-process.
Measurement of charm fragmentation ratios and fractions in photoproduction at HERA
The production of D(*+), D(0), D(+), D(s)(+) and Lambda(+)(c) charm hadrons and their antiparticles in ep scattering at HERA was measured with the ZEUS detector using an integrated luminosity of 79 pb(-1). The measurement has been performed in the photoproduction regime with the exchanged-photon virtuality Q(2) < 1 GeV(2) and for photon-proton centre-of-mass energies in the range 130 < W < 300 GeV. The charm hadrons were reconstructed in the range of transverse momentum PT (D, A,) > 3.8 GeV and pseudorapidity vertical bar eta(D, Lambda(c))vertical bar < 1.6. The production cross sections were used to determine the ratio of neutral and charged D-meson production rates, R(u/d), the strangeness-suppression factor, gamma(s), and the fraction of charged D mesons produced in a vector state, P(v)(d). The measured R(u/d) and gamma(s), values agree with those obtained in deep inelastic scattering and in e(+)e(-) annihilations. The measured P(v)(d) value is smaller than, but consistent with, the previous measurements. The fractions of c quarks hadronising as a particular charm hadron, f(c -> D, Lambda(c)), were derived in the given kinematic range. The measured open-charm fragmentation fractions are consistent with previous results, although the measured f(c -> D(*+)) is smaller and f (c -> Lambda(+)(c)) is larger than those obtained in e(+)e(-) annihilations. These results generally support the hypothesis that fragmentation proceeds independently of the hard sub-process.
The production of D(*+), D(0), D(+), D(s)(+) and Lambda(+)(c) charm hadrons and their antiparticles in ep scattering at HERA was measured with the ZEUS detector using an integrated luminosity of 79 pb(-1). The measurement has been performed in the photoproduction regime with the exchanged-photon virtuality Q(2) < 1 GeV(2) and for photon-proton centre-of-mass energies in the range 130 < W < 300 GeV. The charm hadrons were reconstructed in the range of transverse momentum PT (D, A,) > 3.8 GeV and pseudorapidity vertical bar eta(D, Lambda(c))vertical bar < 1.6. The production cross sections were used to determine the ratio of neutral and charged D-meson production rates, R(u/d), the strangeness-suppression factor, gamma(s), and the fraction of charged D mesons produced in a vector state, P(v)(d). The measured R(u/d) and gamma(s), values agree with those obtained in deep inelastic scattering and in e(+)e(-) annihilations. The measured P(v)(d) value is smaller than, but consistent with, the previous measurements. The fractions of c quarks hadronising as a particular charm hadron, f(c -> D, Lambda(c)), were derived in the given kinematic range. The measured open-charm fragmentation fractions are consistent with previous results, although the measured f(c -> D(*+)) is smaller and f (c -> Lambda(+)(c)) is larger than those obtained in e(+)e(-) annihilations. These results generally support the hypothesis that fragmentation proceeds independently of the hard sub-process.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/20.500.11770/126848
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simulazione ASN
Il report seguente simula gli indicatori relativi alla propria produzione scientifica in relazione alle soglie ASN 2023-2025 del proprio SC/SSD. Si ricorda che il superamento dei valori soglia (almeno 2 su 3) è requisito necessario ma non sufficiente al conseguimento dell'abilitazione. La simulazione si basa sui dati IRIS e sugli indicatori bibliometrici alla data indicata e non tiene conto di eventuali periodi di congedo obbligatorio, che in sede di domanda ASN danno diritto a incrementi percentuali dei valori. La simulazione può differire dall'esito di un’eventuale domanda ASN sia per errori di catalogazione e/o dati mancanti in IRIS, sia per la variabilità dei dati bibliometrici nel tempo. Si consideri che Anvur calcola i valori degli indicatori all'ultima data utile per la presentazione delle domande.
La presente simulazione è stata realizzata sulla base delle specifiche raccolte sul tavolo ER del Focus Group IRIS coordinato dall’Università di Modena e Reggio Emilia e delle regole riportate nel DM 589/2018 e allegata Tabella A. Cineca, l’Università di Modena e Reggio Emilia e il Focus Group IRIS non si assumono alcuna responsabilità in merito all’uso che il diretto interessato o terzi faranno della simulazione. Si specifica inoltre che la simulazione contiene calcoli effettuati con dati e algoritmi di pubblico dominio e deve quindi essere considerata come un mero ausilio al calcolo svolgibile manualmente o con strumenti equivalenti.
