This Letter presents the first measurement of the impact-parameter dependent angular anisotropy in the decay of coherently photoproduced Rho0 mesons. The Rho0 mesons are reconstructed through their decay into pion pairs. The measured anisotropy corresponds to the amplitude of the cos(2Phi) modulation, where Phi is the angle between the two vectors formed by the sum and the difference of the transverse momenta of the pions, respectively. The measurement was performed by the ALICE Collaboration at the LHC using data from ultraperipheral Pb–Pb collisions at a center-of-mass energy of sqrt(sNN) = 5.02 TeV per nucleon pair. Different impact-parameter regions are selected by classifying the events in nuclear-breakup classes. The amplitude of the cos(2Phi) modulation is found to increase by about one order of magnitude from large to small impact parameters. Theoretical calculations describe the measured cos(2Phi) anisotropy and its impact-parameter dependence as the result of a quantum interference effect at the femtometer scale, arising from the ambiguity regarding which of the nuclei is the photon source in the interaction.

Acharya, S., Adamová, D., Agarwal, A., Aglieri Rinella, G., Aglietta, L., Agnello, M., et al. (2024). Measurement of the impact-parameter dependent azimuthal anisotropy in coherent Rho0 photoproduction in Pb–Pb collisions at sqrt(sNN)=5.02 TeV. PHYSICS LETTERS. SECTION B, 858, 1-14 [10.1016/j.physletb.2024.139017].

Measurement of the impact-parameter dependent azimuthal anisotropy in coherent Rho0 photoproduction in Pb–Pb collisions at sqrt(sNN)=5.02 TeV

Agrawal, N.;Alici, A.;Arcelli, S.;Bellini, F.;Colocci, M.;Ercolessi, F.;Jacazio, N.;Malfattore, G.;Rubini, N.;Scioli, G.;Strazzi, S.;Tomassini, S.;
2024

Abstract

This Letter presents the first measurement of the impact-parameter dependent angular anisotropy in the decay of coherently photoproduced Rho0 mesons. The Rho0 mesons are reconstructed through their decay into pion pairs. The measured anisotropy corresponds to the amplitude of the cos(2Phi) modulation, where Phi is the angle between the two vectors formed by the sum and the difference of the transverse momenta of the pions, respectively. The measurement was performed by the ALICE Collaboration at the LHC using data from ultraperipheral Pb–Pb collisions at a center-of-mass energy of sqrt(sNN) = 5.02 TeV per nucleon pair. Different impact-parameter regions are selected by classifying the events in nuclear-breakup classes. The amplitude of the cos(2Phi) modulation is found to increase by about one order of magnitude from large to small impact parameters. Theoretical calculations describe the measured cos(2Phi) anisotropy and its impact-parameter dependence as the result of a quantum interference effect at the femtometer scale, arising from the ambiguity regarding which of the nuclei is the photon source in the interaction.
2024
Acharya, S., Adamová, D., Agarwal, A., Aglieri Rinella, G., Aglietta, L., Agnello, M., et al. (2024). Measurement of the impact-parameter dependent azimuthal anisotropy in coherent Rho0 photoproduction in Pb–Pb collisions at sqrt(sNN)=5.02 TeV. PHYSICS LETTERS. SECTION B, 858, 1-14 [10.1016/j.physletb.2024.139017].
Acharya, S.; Adamová, D.; Agarwal, A.; Aglieri Rinella, G.; Aglietta, L.; Agnello, M.; Agrawal, N.; Ahammed, Z.; Ahmad, S.; Ahn, S.U.; Ahuja, I.; Akin...espandi
File in questo prodotto:
Eventuali allegati, non sono esposti

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11585/995344
 Attenzione

Attenzione! I dati visualizzati non sono stati sottoposti a validazione da parte dell'ateneo

Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 0
  • ???jsp.display-item.citation.isi??? ND
social impact