Photoproduction of <i>K</i><SUP>+</SUP> <i>K</i><SUP>-</SUP> Pairs in Ultraperipheral Collisions


Acharya S., Adamová D., Aglieri Rinella G., Agnello M., Agrawal N., Ahammed Z., ...Daha Fazla

PHYSICAL REVIEW LETTERS, cilt.132, sa.22, 2024 (SCI-Expanded, Scopus) identifier identifier identifier identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 132 Sayı: 22
  • Basım Tarihi: 2024
  • Doi Numarası: 10.1103/physrevlett.132.222303
  • Dergi Adı: PHYSICAL REVIEW LETTERS
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Yıldız Teknik Üniversitesi Adresli: Evet

Özet

K+K- pairs may be produced in photonuclear collisions, either from the decays of photoproduced phi(1020) mesons or directly as nonresonant K+K- pairs. Measurements of K+K- photoproduction probe the couplings between the phi(1020) and charged kaons with photons and nuclear targets. The kaon-proton scattering occurs at energies far above those available elsewhere. We present the first measurement of coherent photoproduction of K+K- pairs on lead ions in ultraperipheral collisions using the ALICE detector, including the first investigation of direct K+K- production. There is significant KthornK- production at low transverse momentum, consistent with coherent photoproduction on lead targets. In the mass range 1.1 < M-KK < 1.4 GeV=c(2) above the phi(1020) resonance, for rapidity vertical bar y(KK)vertical bar < 0.8 and p(T,) (KK) < 0.1 GeV/c, the measured coherent photoproduction cross section is d sigma=dy = 3.37 +/- 0.61 (stat) +/- 0.15(syst) mb. The center-of-mass energy per nucleon of the photon-nucleus (Pb) systemW(gamma Pb,n) ranges from 33 to 188 GeV, far higher than previous measurements on heavy-nucleus targets. The cross section is larger than expected for phi(1020) photoproduction alone. The mass spectrum is fit to a cocktail consisting of phi (1020) decays, direct K+K- photoproduction, and interference between the two. The confidence regions for the amplitude and relative phase angle for direct K+K- photoproduction are presented.