16 «Â³ñíèê Õàðê³âñüêîãî óí³âåðñèòåòó», ¹ 845, 2009 ñåð³ÿ ô³çè÷íà «ßäðà, ÷àñòèíêè, ïîëÿ», âèï. 1 /41/ Â.Â. Êîòëÿð, Í.È. Ìàñëîâ... Ìãíîâåííûå ôîòîíû â ïðîòîí... ɍȾɄ 539.172 ɆȽɇɈȼȿɇɇɕȿ ɎɈɌɈɇɕ ȼ ɉɊɈɌɈɇ – ɉɊɈɌɈɇɇɈɆ ɊȺɋɋȿəɇɂɂ ɇȺ ȻɈɅɖɒɈɆ ȺȾɊɈɇɇɈɆ ɄɈɅɅȺɃȾȿɊȿ * ɇɚɰɢɨɧɚɥɶɧɵɣ ɇɚɭɱɧɵɣ ɐɟɧɬɪ «ɏɚɪɶɤɨɜɫɤɢɣ Ɏɢɡɢɤɨ-Ɍɟɯɧɢɱɟɫɤɢɣ ɂɧɫɬɢɬɭɬ» ɭɥ. Ⱥɤɚɞɟɦɢɱɟɫɤɚɹ 1, ɝ. ɏɚɪɶɤɨɜ, 61108, ɍɤɪɚɢɧɚ E-mail: kotlyarv@kipt.kharkov.ua ** ɏɚɪɶɤɨɜɫɤɢɣ ɧɚɰɢɨɧɚɥɶɧɵɣ ɭɧɢɜɟɪɫɢɬɟɬ ɢɦ. ȼ.ɇ. Ʉɚɪɚɡɢɧɚ ɩɥ. ɋɜɨɛɨɞɵ, 4, ɝ. ɏɚɪɶɤɨɜ, 61077, ɍɤɪɚɢɧɚ ɉɨɫɬɭɩɢɥɚ ɜ ɪɟɞɚɤɰɢɸ 16 ɹɧɜɚɪɹ 2009 ɝ. ɋ ɩɨɦɨɳɶɸ ɝɟɧɟɪɚɬɨɪɚ ɫɨɛɵɬɢɣ ɉɢɮɢɹ ɢɡɭɱɚɟɬɫɹ ɪɨɠɞɟɧɢɟ ɦɝɧɨɜɟɧɧɵɯ ɮɨɬɨɧɨɜ ɜ ɪɟɚɤɰɢɢ pp ‘ JX. ȼɵɱɢɫɥɟɧɢɹ ɩɪɨɜɟɞɟɧɵ ɩɪɢ ɷɧɟɪɝɢɹɯ s = 2…14 Ɍɷȼ ɜ ɨɛɥɚɫɬɢ ɩɨɩɟɪɟɱɧɵɯ ɢɦɩɭɥɶɫɨɜ ɪɌ < 100 Ƚɷȼ/ɫ ɢ ɩɫɟɜɞɨɛɵɫɬɪɨɬ |K| < 10. ɂɫɫɥɟɞɨɜɚɧɚ ɨɬɧɨɫɢɬɟɥɶɧɚɹ ɪɨɥɶ ɦɟɯɚɧɢɡɦɨɜ pp ‘ JX ɤɚɤ ɜ ɥɢɞɢɪɭɸɳɟɦ ɩɨɪɹɞɤɟ ɬɟɨɪɢɢ ɜɨɡɦɭɳɟɧɢɣ ɄɏȾ, ɬɚɤ ɢ ɫ ɭɱɟɬɨɦ ɩɨɩɪɚɜɨɤ ɛɨɥɟɟ ɜɵɫɨɤɢɯ ɩɨɪɹɞɤɨɜ ɩɨ ɤɨɧɫɬɚɧɬɚɦ ɫɢɥɶɧɨɝɨ ɢ ɷɥɟɤɬɪɨɦɚɝɧɢɬɧɨɝɨ ɜɡɚɢɦɨɞɟɣɫɬɜɢɣ. Ɋɚɫɫɦɨɬɪɟɧɵ ɫɩɟɤɬɪɵ ɢɡɨɥɢɪɨɜɚɧɧɵɯ ɮɨɬɨɧɨɜ, ɤɨɬɨɪɵɟ ɦɨɝɭɬ ɛɵɬɶ ɢɡɦɟɪɟɧɵ ɫ ɩɨɦɨɳɶɸ ɮɨɬɨɧɧɨɝɨ ɫɩɟɤɬɪɨɦɟɬɪɚ PHOS ɜ ɷɤɫɩɟɪɢɦɟɧɬɟ ALICE ɧɚ ɛɨɥɶɲɨɦ ɚɞɪɨɧɧɨɦ ɤɨɥɥɚɣɞɟɪɟ (LHC). Ɋɚɫɫɱɢɬɚɧɧɵɟ ɫɟɱɟɧɢɹ ɫɪɚɜɧɢɜɚɸɬɫɹ ɫ ɪɟɡɭɥɶɬɚɬɚɦɢ ɞɪɭɝɢɯ ɚɜɬɨɪɨɜ ɢ ɫ ɷɤɫɩɟɪɢɦɟɧɬɚɥɶɧɵɦɢ ɞɚɧɧɵɦɢ. ɄɅɘɑȿȼɕȿ ɋɅɈȼȺ: ɝɟɧɟɪɚɬɨɪ ɫɨɛɵɬɢɣ ɉɢɮɢɹ, ɦɝɧɨɜɟɧɧɵɟ ɮɨɬɨɧɵ, ɩɪɨɬɨɧ–ɩɪɨɬɨɧɧɨɟ ɪɚɫɫɟɹɧɢɟ, ɮɨɬɨɧɧɵɣ ɫɩɟɤɬɪɨɦɟɬɪ PHOS, ɷɤɫɩɟɪɢɦɟɧɬ ALICE, ɛɨɥɶɲɨɣ ɚɞɪɨɧɧɵɣ ɤɨɥɥɚɣɞɟɪ ȼ.ȼ. Ʉɨɬɥɹɪ*, ɇ.ɂ. Ɇɚɫɥɨɜ*, Ⱥ.Ⱥ. ɓɟɝɥɨɜɚ** Ɇɝɧɨɜɟɧɧɵɟ ɮɨɬɨɧɵ ɪɨɠɞɚɸɬɫɹ ɜ ɠɟɫɬɤɢɯ ɩɚɪɬɨɧ–ɩɚɪɬɨɧɧɵɯ ɩɪɨɰɟɫɫɚɯ ɧɚ ɪɚɧɧɢɯ ɫɬɚɞɢɹɯ ɜ ɩɪɨɬɨɧ– ɩɪɨɬɨɧɧɨɦ ɪɚɫɫɟɹɧɢɢ. ɀɟɫɬɤɢɟ ɮɨɬɨɧɵ ɧɟ ɜɡɚɢɦɨɞɟɣɫɬɜɭɸɬ ɫ ɱɚɫɬɢɰɚɦɢ ɜ ɤɨɧɟɱɧɨɦ ɫɨɫɬɨɹɧɢɢ ɢ ɩɪɟɞɫɬɚɜɥɹɸɬ ɢɧɬɟɪɟɫ ɞɥɹ ɢɫɫɥɟɞɨɜɚɧɢɹ ɜɨɡɦɨɠɧɨɫɬɟɣ ɄɏȾ ɞɥɹ ɨɩɢɫɚɧɢɹ ɩɚɪɬɨɧɧɵɯ ɩɪɨɰɟɫɫɨɜ [1]. ɉɨɫɤɨɥɶɤɭ ɚɦɩɥɢɬɭɞɵ ɩɟɪɜɢɱɧɵɯ ɩɚɪɬɨɧɧɵɯ ɩɪɨɰɟɫɫɨɜ ɡɚɜɢɫɹɬ ɨɬ ɝɥɸɨɧɧɵɯ ɢ ɤɜɚɪɤɨɜɵɯ ɫɬɪɭɤɬɭɪɧɵɯ ɮɭɧɤɰɢɣ, ɚɧɚɥɢɡ ɫɟɱɟɧɢɣ ɪɟɚɤɰɢɢ pp ‘ JX ɜ ɨɛɥɚɫɬɢ ɭɥɶɬɪɚɪɟɥɹɬɢɜɢɫɬɫɤɢɯ ɷɧɟɪɝɢɣ ɦɨɠɟɬ ɞɚɬɶ ɧɨɜɭɸ ɢɧɮɨɪɦɚɰɢɸ ɨ ɫɬɪɭɤɬɭɪɟ ɩɪɨɬɨɧɨɜ ɢ ɨ ɝɥɸɨɧɧɨɣ ɞɢɧɚɦɢɤɟ ɩɪɢ ɦɚɥɵɯ ɡɧɚɱɟɧɢɹɯ ɛɶɟɪɤɟɧɨɜɫɤɨɣ ɩɟɪɟɦɟɧɧɨɣ ɯ. ȼ ɬɨ ɠɟ ɜɪɟɦɹ ɦɝɧɨɜɟɧɧɵɟ ɮɨɬɨɧɵ ɦɨɝɭɬ ɛɵɬɶ ɢɫɩɨɥɶɡɨɜɚɧɵ ɞɥɹ ɜɵɞɟɥɟɧɢɹ ɫɬɪɭɣ ɫɪɟɞɢ ɩɪɨɞɭɤɬɨɜ ɪɟɚɤɰɢɢ ɢ ɨɩɪɟɞɟɥɟɧɢɹ ɢɯ ɫɭɦɦɚɪɧɨɣ ɷɧɟɪɝɢɢ [2]. ɂɫɫɥɟɞɨɜɚɧɢɟ ɩɪɨɰɟɫɫɨɜ ɪɨɠɞɟɧɢɹ ɦɝɧɨɜɟɧɧɵɯ ɮɨɬɨɧɨɜ ɩɪɨɜɨɞɢɥɨɫɶ ɦɧɨɝɢɦɢ ɷɤɫɩɟɪɢɦɟɧɬɚɥɶɧɵɦɢ ɤɨɥɥɚɛɨɪɚɰɢɹɦɢ, ɧɚɩɪɢɦɟɪ CDF ɢ D0 ɜ ɥɚɛɨɪɚɬɨɪɢɢ ɢɦ. Ɏɟɪɦɢ [3–5], ɢ ɜɤɥɸɱɟɧɨ ɜ ɩɪɨɝɪɚɦɦɭ ɷɤɫɩɟɪɢɦɟɧɬɨɜ ALICE [6–8], CMS ɢ ATLAS ɧɚ ɛɨɥɶɲɨɦ ɚɞɪɨɧɧɨɦ ɤɨɥɥɚɣɞɟɪɟ. ɐɟɥɶɸ ɞɚɧɧɨɣ ɪɚɛɨɬɵ ɹɜɥɹɟɬɫɹ ɦɨɞɟɥɢɪɨɜɚɧɢɟ ɩɪɨɰɟɫɫɨɜ ɪɨɠɞɟɧɢɹ ɦɝɧɨɜɟɧɧɵɯ ɮɨɬɨɧɨɜ ɜ ɩɪɨɬɨɧ– ɩɪɨɬɨɧɧɨɦ ɪɚɫɫɟɹɧɢɢ ɜ ɭɫɥɨɜɢɹɯ ɷɤɫɩɟɪɢɦɟɧɬɨɜ ɧɚ LHC, ɚɧɚɥɢɡ ɢɫɬɨɱɧɢɤɨɜ ɮɨɧɚ ɢ ɦɟɬɨɞɨɜ ɟɝɨ ɩɨɞɚɜɥɟɧɢɹ ɜ ɢɡɦɟɪɟɧɢɹɯ ɫ ɩɨɦɨɳɶɸ ɞɟɬɟɤɬɨɪɚ PHOS [9–11] ɜ ɷɤɫɩɟɪɢɦɟɧɬɟ ALICE. ɉɈȾɏɈȾ, ɊȿɁɍɅɖɌȺɌɕ ɂ ɈȻɋɍɀȾȿɇɂȿ Ⱦɥɹ ɦɨɞɟɥɢɪɨɜɚɧɢɹ ɜɡɚɢɦɨɞɟɣɫɬɜɢɹ ɭɥɶɬɪɚɪɟɥɹɬɢɜɢɫɬɫɤɢɯ ɩɪɨɬɨɧɨɜ ɜ ɪɚɛɨɬɟ ɢɫɩɨɥɶɡɨɜɚɧ ɝɟɧɟɪɚɬɨɪ ɫɨɛɵɬɢɣ ɉɢɮɢɹ [12]. Ɋɚɫɱɟɬɵ ɩɪɨɜɨɞɢɥɢɫɶ ɫ ɩɪɨɝɪɚɦɦɨɣ PYTHIA ɜɟɪɫɢɢ 6.4.19 ɨɬ 23.10.2008 ɫ ɮɭɧɤɰɢɹɦɢ ɪɚɫɩɪɟɞɟɥɟɧɢɹ ɩɚɪɬɨɧɨɜ CTEQ 5L [13]. Ʉɚɤ ɜɢɞɧɨ ɢɡ ɪɢɫ. 1, ɩɨɥɭɱɟɧɧɵɟ ɩɨɥɧɵɟ ɫɟɱɟɧɢɹ ɪɟɚɤɰɢɢ pp → X ɭɞɨɜɥɟɬɜɨɪɢɬɟɥɶɧɨ ɫɨɝɥɚɫɭɸɬɫɹ ɫ ɷɤɫɩɟɪɢɦɟɧɬɚɥɶɧɵɦɢ ɞɚɧɧɵɦɢ [14] ɩɪɢ ɷɧɟɪɝɢɹɯ s = 2…14 Ɍɷȼ. ɉɪɢ ɜɵɱɢɫɥɟɧɢɢ ɫɩɟɤɬɪɨɜ ɦɝɧɨɜɟɧɧɵɯ ɮɨɬɨɧɨɜ ɛɵɥɢ ɭɱɬɟɧɵ ɤɜɚɪɤ–ɝɥɸɨɧɧɨɟ ɪɚɫɫɟɹɧɢɟ ɤɨɦɩɬɨɧɨɜɫɤɨɝɨ ɬɢɩɚ qg → qγ , ɤɜɚɪɤ–ɚɧɬɢɤɜɚɪɤɨɜɚɹ ɚɧɧɢɝɢɥɹɰɢɹ qq → gγ , ɚ ɬɚɤɠɟ ɩɚɪɬɨɧɧɵɟ ɩɪɨɰɟɫɫɵ gg → gγ , qq → γγ , gg → γγ . ɂɡ ɫɪɚɜɧɟɧɢɹ ɩɨɥɧɵɯ ɫɟɱɟɧɢɣ, ɤɨɬɨɪɵɟ ɩɪɢɜɟɞɟɧɵ ɜ ɬɚɛɥ. 1, ɜɢɞɧɨ, ɱɬɨ ɞɨɦɢɧɢɪɭɸɳɢɦ ɩɪɨɰɟɫɫɨɦ ɪɨɠɞɟɧɢɹ ɦɝɧɨɜɟɧɧɵɯ ɮɨɬɨɧɨɜ ɹɜɥɹɟɬɫɹ ɤɜɚɪɤ–ɝɥɸɨɧɧɨɟ ɤɨɦɩɬɨɧɨɜɫɤɨɟ ɪɚɫɫɟɹɧɢɟ. Ⱦɪɭɝɢɟ ɪɚɫɫɦɨɬɪɟɧɧɵɟ ɩɪɨɰɟɫɫɵ ɢɝɪɚɸɬ ɪɨɥɶ ɧɟɛɨɥɶɲɢɯ ɩɨɩɪɚɜɨɤ ɜ ɢɡɭɱɚɟɦɨɣ ɨɛɥɚɫɬɢ ɷɧɟɪɝɢɣ. Nγ ɂɡ ɪɚɫɱɟɬɨɜ ɫɥɟɞɭɟɬ, ɱɬɨ ɩɪɢ s = 1,96; 5,5 ɢ 14 Ɍɷȼ ɤɚɠɞɵɣ ɦɝɧɨɜɟɧɧɵɣ ɮɨɬɨɧ ɫɨɩɪɨɜɨɠɞɚɟɬɫɹ decay ~ 42, 50 ɢ 57 “ɪɚɫɩɚɞɧɵɦɢ” ɮɨɬɨɧɚɦɢ, ɢɡ ɤɨɬɨɪɵɯ ɜ ɫɪɟɞɧɟɦ 93% ɮɨɬɨɧɨɜ ɩɪɨɢɫɯɨɞɹɬ ɢɡ ɪɚɫɩɚɞɨɜ π 0 → γγ . Ɂɚɜɢɫɢɦɨɫɬɶ ɨɬɧɨɲɟɧɢɹ ɫɩɟɤɬɪɨɜ ɦɝɧɨɜɟɧɧɵɯ ɢ ɮɨɧɨɜɵɯ ɮɨɬɨɧɨɜ ɨɬ ɩɨɩɟɪɟɱɧɵɯ ɢɦɩɭɥɶɫɨɜ pT ɩɨɤɚɡɚɧɚ ɧɚ ɪɢɫ. 2. ɋɩɥɨɲɧɚɹ ɤɪɢɜɚɹ ɩɨɥɭɱɟɧɚ c ɭɱɟɬɨɦ ɮɨɧɚ ɜ ɨɛɥɚɫɬɢ ɚɡɢɦɭɬɚɥɶɧɵɯ ɭɝɥɨɜ ϕ = 0360$ ɢ ɩɫɟɜɞɨɛɵɫɬɪɨɬ η = 010. ɋ ɪɨɫɬɨɦ ɩɨɩɟɪɟɱɧɵɯ ɢɦɩɭɥɶɫɨɜ ɜ ɨɛɥɚɫɬɢ pT > 5 Ƚɷȼ/c ɮɨɧ ɧɟɡɧɚɱɢɬɟɥɶɧɨ ɭɦɟɧɶɲɚɟɬɫɹ ɢ ɨɬɧɨɲɟɧɢɟ ɫɩɟɤɬɪɨɜ r(pT ) = nγ prompt(pT ) / nγ backgr(pT ) ɩɪɢɧɢɦɚɟɬ ɡɧɚɱɟɧɢɹ r(pT ) G0,1. Ɏɨɧ, ɨɛɭɫɥɨɜɥɟɧɧɵɣ “ɪɚɫɩɚɞɧɵɦɢ” ɢ ɞɪ. ɝɚɦɦɚ–ɤɜɚɧɬɚɦɢ, ɦɨɠɟɬ ɛɵɬɶ ɩɨɞɚɜɥɟɧ ɜ ɢɡɦɟɪɟɧɢɹɯ, ɤɨɝɞɚ 17 ñåð³ÿ ô³çè÷íà «ßäðà, ÷àñòèíêè, ïîëÿ», âèï. 1 /41/ Ìãíîâåííûå ôîòîíû â ïðîòîí... ɢɞɟɧɬɢɮɢɤɚɰɢɹ ɦɝɧɨɜɟɧɧɵɯ ɮɨɬɨɧɨɜ ɫ ɛɨɥɶɲɢɦɢ ɩɨɩɟɪɟɱɧɵɦɢ ɢɦɩɭɥɶɫɚɦɢ ɩɪɨɢɡɜɨɞɢɬɫɹ ɫ ɢɫɩɨɥɶɡɨɜɚɧɢɟɦ ɤɨɪɪɟɥɹɰɢɣ ɮɨɬɨɧ–ɫɬɪɭɹ ɢɥɢ ɧɚ ɨɫɧɨɜɟ ɦɟɬɨɞɚ ɢɡɨɥɹɰɢɢ [15,16]. Ɏɨɬɨɧɵ, ɨɛɪɚɡɭɸɳɢɟɫɹ ɜ ɪɚɫɩɚɞɚɯ π 0 – ɦɟɡɨɧɨɜ, ɦɨɝɭɬ ɛɵɬɶ ɜɵɞɟɥɟɧɵ ɧɚ ɨɫɧɨɜɟ ɚɧɚɥɢɡɚ ɢɧɜɚɪɢɚɧɬɧɵɯ ɦɚɫɫ ɩɚɪ ɮɨɬɨɧɨɜ. Ɍɚɛɥɢɰɚ 1. ȼɤɥɚɞɵ ɩɚɪɬɨɧɧɵɯ ɩɪɨɰɟɫɫɨɜ ɜ ɩɨɥɧɵɟ ɫɟɱɟɧɢɹ ɪɨɠɞɟɧɢɹ ɦɝɧɨɜɟɧɧɵɯ ɮɨɬɨɧɨɜ ɜ ɪɟɚɤɰɢɢ pp → γ X s , Ɍɷȼ 1,96 5,5 14,0 σ (qg → qγ ) , ɦɛ 5,012º10 9,715º10-2 0,1634 -2 σ (qq → gγ ) , ɦɛ 2,943º10 4,613º10-3 6,846º10-3 -3 σ ( gg → gγ ) , ɦɛ 2,357º10 5,250º10-4 1,032º10-3 -4 σ ( gg → γγ ) , ɦɛ 7,536º10 1,738º10-4 3,446º10-4 -5 σ (qq → γγ ) , ɦɛ 9,120º10-6 1,480º10-5 2,242º10-5 Ɋɢɫ.1. ɗɧɟɪɝɟɬɢɱɟɫɤɚɹ ɡɚɜɢɫɢɦɨɫɬɶ ɩɨɥɧɨɝɨ ɫɟɱɟɧɢɹ ɪɟɚɤɰɢɢ Ɋɢɫ.2. Ɉɬɧɨɲɟɧɢɟ ɫɩɟɤɬɪɨɜ ɦɝɧɨɜɟɧɧɵɯ ɢ ɮɨɧɨɜɵɯ ɮɨɬɨɧɨɜ ɩɪɢ s = 5,5 Ɍɷȼ. Ɋɚɡɥɢɱɢɹ ɦɟɠɞɭ ɫɩɥɨɲɧɨɣ ɢ ɲɬɪɢɯɨɜɨɣ ɤɪɢɜɵɦɢ ɭɤɚɡɚɧɵ ɜ ɬɟɤɫɬɟ. pp → X. Ɍɨɱɤɚɦɢ š ɩɨɤɚɡɚɧɵ ɪɟɡɭɥɶɬɚɬɵ ɜɵɱɢɫɥɟɧɢɣ ɫ ɩɨɦɨɳɶɸ PYTHIA. ɗɤɫɩɟɪɢɦɟɧɬɚɥɶɧɵɟ ɞɚɧɧɵɟ Å, Õ ɢ ɤɪɢɜɚɹ ɜɡɹɬɵ ɢɡ [14]. Ⱦɟɣɫɬɜɢɬɟɥɶɧɨ, ɞɥɹ ɦɝɧɨɜɟɧɧɵɯ ɮɨɬɨɧɨɜ, ɤɨɬɨɪɵɟ ɢɞɟɧɬɢɮɢɰɢɪɨɜɚɧɵ ɫ ɩɨɦɨɳɶɸ ɤɚɤɨɝɨ–ɥɢɛɨ ɢɡ ɭɤɚɡɚɧɧɵɯ ɫɩɨɫɨɛɨɜ, ɨɬɧɨɲɟɧɢɟ ɫɩɟɤɬɪɨɜ r(pT ) ɭɜɟɥɢɱɢɜɚɟɬɫɹ ɛɨɥɟɟ ɱɟɦ 104 ɪɚɡ, ɤɚɤ ɫɥɟɞɭɟɬ ɢɡ ɫɪɚɜɧɟɧɢɹ ɲɬɪɢɯɨɜɨɣ ɢ ɫɩɥɨɲɧɵɯ ɤɪɢɜɵɯ ɧɚ ɪɢɫ.2. ɒɬɪɢɯɨɜɚɹ ɤɪɢɜɚɹ ɫɨɨɬɜɟɬɫɬɜɭɟɬ ɪɚɫɱɟɬɚɦ, ɜ ɤɨɬɨɪɵɯ ɫɩɟɤɬɪ n γ backgr ( pT ) ɨɩɪɟɞɟɥɹɥɫɹ ɨɤɪɟɫɬɧɨɫɬɶɸ ∆η ⋅ ∆ϕ ɬɨɱɤɢ ηγ ,ϕγ , ɝɞɟ ∆ϕ = 5, 2 ⋅ 10−3 ɢ ∆η = 0,5. Ʉɨɨɪɞɢɧɚɬɵ ηγ ,ϕγ ɡɚɞɚɸɬɫɹ ɧɚɩɪɚɜɥɟɧɢɟɦ ɜɟɤɬɨɪɚ ɢɦɩɭɥɶɫɚ ɦɝɧɨɜɟɧɧɨɝɨ ɮɨɬɨɧɚ. ɒɬɪɢɯɨɜɚɹ ɤɪɢɜɚɹ ɩɨɥɭɱɟɧɚ ɞɥɹ ɫɩɟɤɬɪɨɜ p ³0 2 dpT n γ 8 prompt ( pT ) ! 2,46 ⋅10 , p ³0 1 dpT n γ backgr ( pT ) ! 2,59 ⋅10 5 , p ³ p12 dpT n γ backgr ( pT ) =0, ɝɞɟ p1 = 5 Ƚɷȼ/c ɢ p2 = 20 Ƚɷȼ/c. Ɋɚɡɥɢɱɢɹ ɦɟɠɞɭ ɫɩɥɨɲɧɨɣ ɢ ɲɬɪɢɯɨɜɨɣ ɤɪɢɜɵɦɢ ɜ ɡɧɚɱɢɬɟɥɶɧɨɣ ɫɬɟɩɟɧɢ ɫɜɹɡɚɧɵ ɫ ɪɚɡɦɟɪɨɦ ɨɛɥɚɫɬɢ, ɤɨɬɨɪɚɹ ɞɚɟɬ ɜɤɥɚɞ ɜ ɫɩɟɤɬɪ ɮɨɧɨɜɵɯ ɮɨɬɨɧɨɜ. ȼ ɩɟɪɜɨɦ ɫɥɭɱɚɟ ɷɬɚ ɨɛɥɚɫɬɶ ɫɨɜɩɚɞɚɟɬ ɫɨ ɜɫɟɦ ɢɧɬɟɪɜɚɥɨɦ ɢɡɦɟɧɟɧɢɹ ϕ ,η , ɜɨ ɜɬɨɪɨɦ — ɨɤɪɟɫɬɧɨɫɬɶɸ ∆η ⋅ ∆ϕ ɬɨɱɤɢ ηγ ,ϕγ . ɂɫɩɨɥɶɡɨɜɚɧɧɚɹ ɜ ɪɚɫɱɟɬɚɯ ɜɟɥɢɱɢɧɚ ∆ϕ ɛɥɢɡɤɚ ɤ ∆ϕ PHOS = 4,9 ⋅10 −3 ɞɥɹ ɮɨɬɨɧɧɨɝɨ ɫɩɟɤɬɪɨɦɟɬɪɚ PHOS. Ⱦɥɹ ɭɫɤɨɪɟɧɢɹ ɪɚɫɱɟɬɨɜ ɛɵɥɨ ɜɵɛɪɚɧɨ ɡɧɚɱɟɧɢɟ ∆η , ɡɧɚɱɢɬɟɥɶɧɨ ɩɪɟɜɵɲɚɸɳɟɟ ∆η PHOS G 5 ⋅10 −3. Ɉɬɦɟɬɢɦ, ɱɬɨ ɬɨɱɧɨɫɬɶ, ɫ ɤɨɬɨɪɨɣ ɢɡɜɟɫɬɧɵ ηγ ,ϕγ ɜ ɤɨɪɪɟɥɹɰɢɨɧɧɵɯ ɢɡɦɟɪɟɧɢɹɯ ɮɨɬɨɧ–ɫɬɪɭɹ, ɡɚɜɢɫɢɬ ɨɬ ɜɟɥɢɱɢɧɵ R = ((η − η jet ) 2 + (ϕ − ϕ jet ) 2 )1/ 2 , ɯɚɪɚɤɬɟɪɢɡɭɸɳɢɣ ɤɨɧɭɫ ɜɨɤɪɭɝ ɧɚɩɪɚɜɥɟɧɢɹ ɫɬɪɭɢ. ɇɚɩɪɢɦɟɪ, ɫɨɝɥɚɫɧɨ [17], R ~1. Ɋɚɫɫɦɨɬɪɢɦ ɫɜɨɣɫɬɜɚ ɞɢɮɮɟɪɟɧɰɢɚɥɶɧɵɯ ɫɟɱɟɧɢɣ ɪɨɠɞɟɧɢɹ ɦɝɧɨɜɟɧɧɵɯ ɮɨɬɨɧɨɜ ɜ ɪɟɚɤɰɢɢ pp → γ X. ɋɟɱɟɧɢɹ d 2σ ( pT ,η ) / dpT dη ɷɤɫɩɨɧɟɧɰɢɚɥɶɧɨ ɭɛɵɜɚɸɬ ɫ ɭɜɟɥɢɱɟɧɢɟɦ ɩɨɩɟɪɟɱɧɨɝɨ ɢɦɩɭɥɶɫɚ. Ʉɚɤ ɩɨɤɚɡɚɧɨ ɧɚ ɪɢɫ. 3ɚ, ɫɤɨɪɨɫɬɶ ɭɛɵɜɚɧɢɹ ɫɟɱɟɧɢɣ d 2σ ( pT ,η = Const ) / dpT dη ɡɚɦɟɬɧɨ ɡɚɜɢɫɢɬ ɨɬ ɩɫɟɜɞɨɛɵɫɬɪɨɬɵ η . ɂɡ ɪɢɫ. 3ɛ ɜɢɞɧɨ, ɱɬɨ ɫɟɱɟɧɢɹ d 2σ ( pT = Const ,η ) / dpT dη ɹɜɥɹɸɬɫɹ ɦɟɞɥɟɧɧɨ ɢɡɦɟɧɹɸɳɢɦɢɫɹ ɮɭɧɤɰɢɹɦɢ ɜ ɡɧɚɱɢɬɟɥɶɧɨɦ ɢɧɬɟɪɜɚɥɟ η , ɩɪɢɱɟɦ ɜɟɥɢɱɢɧɚ ɷɬɨɝɨ ɢɧɬɟɪɜɚɥɚ ɭɦɟɧɶɲɚɟɬɫɹ ɫ ɪɨɫɬɨɦ pT . 18 «Â³ñíèê Õàðê³âñüêîãî óí³âåðñèòåòó», ¹ 845, 2009 Â.Â. Êîòëÿð, Í.È. Ìàñëîâ... ȼɤɥɚɞɵ ɪɚɡɥɢɱɧɵɯ ɨɛɥɚɫɬɟɣ ɩɫɟɜɞɨɛɵɫɬɪɨɬ −η0 ≤ η ≤ η0 ɜ ɫɟɱɟɧɢɹ ɪɨɠɞɟɧɢɹ ɦɝɧɨɜɟɧɧɵɯ ɮɨɬɨɧɨɜ 0 dη d 2σ ( p ,η ) / dp dη dσ ( pT ;η0 ) / dpT = ³η T T −η0 (1) ɩɨɤɚɡɚɧɵ ɧɚ ɪɢɫ. 4. Ʉɪɢɜɵɟ ɫ η 0= ˆ ɩɨɥɭɱɟɧɵ ɧɚ ɨɫɧɨɜɟ ɦɨɞɟɥɢɪɨɜɚɧɢɹ 4,5 ⋅108 ɢ 3,4 ⋅108 ɩɪɨɰɟɫɫɨɜ ɪɨɠɞɟɧɢɹ ɦɝɧɨɜɟɧɧɵɯ ɝɚɦɦɚ–ɤɜɚɧɬɨɜ ɩɪɢ ɷɧɟɪɝɢɹɯ 5,5 ɢ 14 Ɍɷȼ. Ɂɧɚɱɟɧɢɟ η 0= 0,12 ɫɨɨɬɜɟɬɫɬɜɭɟɬ ɜɨɡɦɨɠɧɨɫɬɹɦ ɮɨɬɨɧɧɨɝɨ ɫɩɟɤɬɪɨɦɟɬɪɚ PHOS, ɜɯɨɞɹɳɟɝɨ ɜ ɫɨɫɬɚɜ ɞɟɬɟɤɬɨɪɚ ALICE. Ɋɚɫɱɟɬɵ ɩɨɤɚɡɵɜɚɸɬ, ɱɬɨ ɢɡ 103 ɦɝɧɨɜɟɧɧɵɯ ɮɨɬɨɧɨɜ, ɨɛɪɚɡɭɸɳɢɯɫɹ ɜ ɪɪ–ɫɨɭɞɚɪɟɧɢɹɯ ɩɪɢ s = 5,514 Ɍɷȼ, ɜ ɨɛɥɚɫɬɶ η < 0,12 ɢ ϕ = 0$ 360$ ɩɨɩɚɞɚɟɬ ɨɤɨɥɨ 14 J–ɤɜɚɧɬɨɜ ɫ pT <100 Ƚɷȼ. ɋ ɩɨɦɨɳɶɸ PHOS ɦɨɝɭɬ ɛɵɬɶ ɡɚɪɟɝɢɫɬɪɢɪɨɜɚɧɵ ɮɨɬɨɧɵ ɜ ɢɧɬɟɪɜɚɥɟ ɭɝɥɨɜ ϕ = 220$ 320$. ɂɡ ɪɢɫ.4 ɬɚɤ ɠɟ ɜɢɞɧɨ, ɱɬɨ ɪɚɫɫɱɢɬɚɧɧɵɟ ɧɚɦɢ ɞɢɮɮɟɪɟɧɰɢɚɥɶɧɵɟ ɫɟɱɟɧɢɹ ɦɝɧɨɜɟɧɧɵɯ ɮɨɬɨɧɨɜ ɩɪɢ ɷɧɟɪɝɢɢ 14 Ɍɷȼ ɛɥɢɡɤɢ ɤ ɪɟɡɭɥɶɬɚɬɚɦ ɜɵɱɢɫɥɟɧɢɣ [18]. Ɋɢɫ.3. Ⱦɢɮɮɟɪɟɧɰɢɚɥɶɧɵɟ ɫɟɱɟɧɢɹ ɪɨɠɞɟɧɢɹ ɦɝɧɨɜɟɧɧɵɯ ɮɨɬɨɧɨɜ ɜ ɪɟɚɤɰɢɢ pp → γ X ɩɪɢ ɷɧɟɪɝɢɢ (ɛ) ɩɪɢɜɟɞɟɧɵ ɡɚɜɢɫɢɦɨɫɬɢ ɫɟɱɟɧɢɣ ɨɬ ɩɫɟɜɞɨɛɵɫɬɪɨɬɵ η ɩɪɢ pTj = 2,5 Ƚɷȼ/ɫ,,57,5 Ƚɷȼ/ɫ ( j = 1,,6). s = 14 Ɍɷȼ. ɇɚ ɱɚɫɬɢ (ɚ) ɪɢɫ. ɩɨɤɚɡɚɧɵ ɫɟɱɟɧɢɹ ɤɚɤ ɮɭɧɤɰɢɢ ɩɨɩɟɪɟɱɧɨɝɨ ɢɦɩɭɥɶɫɚ pT ɞɥɹ ɡɧɚɱɟɧɢɣ ηi = 0,25,,7,75 (i = 1,,5), ɧɚ ɱɚɫɬɢ Ɋɢɫ.4. Ⱦɢɮɮɟɪɟɧɰɢɚɥɶɧɵɟ ɫɟɱɟɧɢɹ (1) ɪɨɠɞɟɧɢɹ ɦɝɧɨɜɟɧɧɵɯ ɮɨɬɨɧɨɜ ɜ ɪɟɚɤɰɢɢ pp → γ X ɚ) — ɩɪɢ ɷɧɟɪɝɢɢ s = 5,5 ɢ ɛ) — 14 Ɍɷȼ. ɋɩɥɨɲɧɵɟ, ɲɬɪɢɯɨɜɵɟ ɢ ɲɬɪɢɯ–ɩɭɧɤɬɢɪɧɵɟ ɤɪɢɜɵɟ ɩɨɥɭɱɟɧɵ ɜ ɞɚɧɧɨɣ ɪɚɛɨɬɟ ɞɥɹ ɡɧɚɱɟɧɢɣ η 0 = ˆ, 1 ɢ 0,12. Ɍɨɱɤɚɦɢ Å ɩɨɤɚɡɚɧɵ ɪɟɡɭɥɶɬɚɬɵ ɜɵɱɢɫɥɟɧɢɣ [18]. Ɋɢɫ.5 ɩɨɤɚɡɵɜɚɟɬ, ɱɬɨ ɫɟɱɟɧɢɹ dσ / dpT ɢ dσ / dη ɹɜɥɹɸɬɫɹ ɜɨɡɪɚɫɬɚɸɳɢɦɢ ɮɭɧɤɰɢɹɦɢ ɷɧɟɪɝɢɢ. ɋ ɭɜɟɥɢɱɟɧɢɟɦ ɷɧɟɪɝɢɢ ɦɚɤɫɢɦɭɦ ɫɟɱɟɧɢɹ dσ (η ) / dη ɫɞɜɢɝɚɟɬɫɹ ɜ ɨɛɥɚɫɬɶ ɛɨɥɶɲɢɯ η ɢ ɨɬɧɨɲɟɧɢɟ ɡɧɚɱɟɧɢɣ ɫɟɱɟɧɢɣ ɜ ɦɚɤɫɢɦɭɦɟ ɢ ɩɪɢ η = 0 ɭɜɟɥɢɱɢɜɚɟɬɫɹ. Ɉɬɧɨɫɢɬɟɥɶɧɚɹ ɪɨɥɶ ɩɟɪɜɢɱɧɵɯ ɩɚɪɬɨɧɧɵɯ ɩɪɨɰɟɫɫɨɜ, ɤɚɤ ɜɢɞɧɨ ɢɡ ɪɢɫ.6, ɧɟ ɢɡɦɟɧɹɟɬɫɹ ɫɭɳɟɫɬɜɟɧɧɨ ɜ ɨɛɥɚɫɬɢ ɩɨɩɟɪɟɱɧɵɯ ɢɦɩɭɥɶɫɨɜ ɞɨ 100 Ƚɷȼ/ɫ. Ʉɜɚɪɤ–ɝɥɸɨɧɧɨɟ ɤɨɦɩɬɨɧɨɜɫɤɨɟ ɪɚɫɫɟɹɧɢɟ qg → qγ ɞɚɟɬ ɨɫɧɨɜɧɨɣ ɜɤɥɚɞ ɤɚɤ ɜ ɩɨɥɧɵɟ, ɬɚɤ ɢ ɜ ɞɢɮɮɟɪɟɧɰɢɚɥɶɧɵɟ ɫɟɱɟɧɢɹ ɪɨɠɞɟɧɢɹ ɦɝɧɨɜɟɧɧɵɯ ɮɨɬɨɧɨɜ ɜ ɪɚɫɫɦɨɬɪɟɧɧɵɯ ɤɢɧɟɦɚɬɢɱɟɫɤɢɯ ɭɫɥɨɜɢɹɯ. Ɋɢɫ.7 ɞɟɦɨɧɫɬɪɢɪɭɟɬ, ɱɬɨ ɝɪɚɧɢɰɚ ɨɛɥɚɫɬɢ ɛɶɟɪɤɟɧɨɜɫɤɨɣ ɩɟɪɟɦɟɧɧɨɣ x, ɤɨɬɨɪɚɹ ɞɨɫɬɭɩɧɚ ɞɥɹ ɢɫɫɥɟɞɨɜɚɧɢɹ ɩɪɢ ɢɡɦɟɪɟɧɢɢ ɫɟɱɟɧɢɣ ɪɨɠɞɟɧɢɹ ɦɝɧɨɜɟɧɧɵɯ ɮɨɬɨɧɨɜ ɜ ɪɟɚɤɰɢɢ pp → γ X, ɢɡɦɟɧɹɟɬɫɹ ɨɬ a 2 ⋅10 −6 ɞɨ a 5 ⋅10 −8 ɩɪɢ ɭɜɟɥɢɱɟɧɢɢ ɷɧɟɪɝɢɢ ɨɬ 1,96 ɞɨ 14 Ɍɷȼ. 19 ñåð³ÿ ô³çè÷íà «ßäðà, ÷àñòèíêè, ïîëÿ», âèï. 1 /41/ Ìãíîâåííûå ôîòîíû â ïðîòîí... Ⱦɟɬɚɥɶɧɵɣ ɚɧɚɥɢɡ ɩɨɤɚɡɵɜɚɟɬ, ɱɬɨ ɫɟɱɟɧɢɹ d 2σ / dpT dη ɨɩɪɟɞɟɥɹɸɬɫɹ ɤɨɧɫɬɚɧɬɨɣ ɷɥɟɤɬɪɨɦɚɝɧɢɬɧɨɝɨ ɜɡɚɢɦɨɞɟɣɫɬɜɢɹ DȿɆ ɜ ɢɧɬɟɪɜɚɥɟ D1GDȿɆGD2, ɝɞɟ D1=1/135 ɢ D2=1/126…1/123 ɞɥɹ ɷɧɟɪɝɢɣ s =2…14 Ɍɷȼ. s ɜ Ʉɨɧɫɬɚɧɬɚ ɫɢɥɶɧɨɝɨ ɜɡɚɢɦɨɞɟɣɫɬɜɢɹ DS ɢɡɦɟɧɹɟɬɫɹ ɨɬ a0,12 ɞɨ a0,46 ɧɟɡɚɜɢɫɢɦɨ ɨɬ ɡɧɚɱɟɧɢɹ ɪɚɫɫɦɨɬɪɟɧɧɨɣ ɨɛɥɚɫɬɢ. Ɋɢɫ.5. Ɂɚɜɢɫɢɦɨɫɬɶ ɞɢɮɮɟɪɟɧɰɢɚɥɶɧɨɝɨ ɫɟɱɟɧɢɹ ɪɟɚɤɰɢɢ pp → γ X ɚ) – ɨɬ ɩɨɩɟɪɟɱɧɨɝɨ ɢɦɩɭɥɶɫɚ pT ɢ ɛ) – ɨɬ ɩɫɟɜɞɨɛɵɫɬɪɨɬɵ η . ɋɩɥɨɲɧɵɟ, ɲɬɪɢɯɨɜɵɟ ɢ ɲɬɪɢɯ–ɩɭɧɤɬɢɪɧɵɟ ɤɪɢɜɵɟ ɪɚɫɫɱɢɬɚɧɵ ɩɪɢ ɷɧɟɪɝɢɹɯ s = 14; 5,5 ɢ 1,96 Ɍɷȼ. Ɋɢɫ.6. ȼɤɥɚɞɵ ɠɟɫɬɤɢɯ ɩɚɪɬɨɧɧɵɯ ɩɪɨɰɟɫɫɨɜ ɜ ɞɢɮɮɟɪɟɧɰɢɚɥɶɧɨɟ ɫɟɱɟɧɢɟ pp → γ X ɩɪɢ s = 5,5 Ɍɷȼ. ɉɪɨɰɟɫɫɚɦ qg → qγ , qq → gγ ɢ gg → gγ ɫɨɨɬɜɟɬɫɬɜɭɸɬ ɫɩɥɨɲɧɚɹ, ɲɬɪɢɯɨɜɚɹ ɢ ɲɬɪɢɯ–ɩɭɧɤɬɢɪɧɚɹ ɤɪɢɜɵɟ. Ɋɢɫ.7. Ɋɚɫɩɪɟɞɟɥɟɧɢɹ ɡɧɚɱɟɧɢɣ ɩɟɪɟɦɟɧɧɨɣ ɯ ɜ ɠɟɫɬɤɨɦ ɪɚɫcɹɧɢɢ ɩɚɪɬɨɧɨɜ. ɋɩɥɨɲɧɚɹ, ɲɬɪɢɯɨɜɚɹ ɢ ɲɬɪɢɯ–ɩɭɧɤɬɢɪɧɚɹ ɤɪɢɜɵɟ ɩɨɥɭɱɟɧɵ ɜ ɪɚɫɱɟɬɚɯ ɩɨɥɧɵɯ ɫɟɱɟɧɢɣ ɪɨɠɞɟɧɢɹ ɦɝɧɨɜɟɧɧɵɯ ɮɨɬɨɧɨɜ ɩɪɢ ɷɧɟɪɝɢɹɯ s = 14; 5,5 ɢ 1,96 Ɍɷȼ. ɁȺɄɅɘɑȿɇɂȿ s ɨɬ 2 ɞɨ 14 Ɍɷȼ, Ɍɚɤɢɦ ɨɛɪɚɡɨɦ, ɩɨɤɚɡɚɧɨ, ɱɬɨ ɩɨɥɧɵɟ ɫɟɱɟɧɢɹ ɪ-ɪ ɪɚɫɫɟɹɧɢɹ ɩɪɢ ɷɧɟɪɝɢɹɯ ɪɚɫɫɱɢɬɚɧɧɵɟ ɫ ɩɨɦɨɳɶɸ ɝɟɧɟɪɚɬɨɪɚ ɫɨɛɵɬɢɣ ɉɢɮɢɹ, ɭɞɨɜɥɟɬɜɨɪɢɬɟɥɶɧɨ ɫɨɝɥɚɫɭɸɬɫɹ ɫ ɷɤɫɩɟɪɢɦɟɧɬɚɥɶɧɵɦɢ ɞɚɧɧɵɦɢ. Ⱦɨɦɢɧɢɪɭɸɳɢɦ ɦɟɯɚɧɢɡɦɨɦ ɪɨɠɞɟɧɢɹ ɦɝɧɨɜɟɧɧɵɯ ɮɨɬɨɧɨɜ ɫ ɩɨɩɟɪɟɱɧɵɦɢ ɢɦɩɭɥɶɫɚɦɢ ɪɌ<100 Ƚɷȼ/c ɜ ɪɟɚɤɰɢɢ ɪɪ → γX ɩɪɢ ɷɧɟɪɝɢɹɯ s =2…14 Ɍɷȼ ɹɜɥɹɟɬɫɹ ɤɨɦɩɬɨɧɨɜɫɤɨɟ ɪɚɫɫɟɹɧɢɟ ɝɥɸɨɧɨɜ qg → qγ. ȼ ɪɚɫɫɦɨɬɪɟɧɧɵɯ ɤɢɧɟɦɚɬɢɱɟɫɤɢɯ ɨɛɥɚɫɬɹɯ ɨɫɧɨɜɧɵɟ ɜɤɥɚɞɵ ɜ ɫɟɱɟɧɢɹ ɪɨɠɞɟɧɢɹ ɦɝɧɨɜɟɧɧɵɯ ɮɨɬɨɧɨɜ ɨɛɭɫɥɨɜɥɟɧɵ ɩɪɨɰɟɫɫɚɦɢ ɜ ɩɟɪɜɨɦ ɧɟɢɫɱɟɡɚɸɳɟɦ ɩɨɪɹɞɤɟ αEM αS ɬɟɨɪɢɢ ɜɨɡɦɭɳɟɧɢɣ. ɉɪɨɰɟɫɫɵ ɛɨɥɟɟ ɜɵɫɨɤɨɝɨ ɩɨɪɹɞɤɚ ɩɨ ɤɨɧɫɬɚɧɬɚɦ ɷɥɟɤɬɪɨɦɚɝɧɢɬɧɨɝɨ ɢ ɫɢɥɶɧɨɝɨ ɜɡɚɢɦɨɞɟɣɫɬɜɢɹ ɹɜɥɹɸɬɫɹ ɦɚɥɵɦɢ ɩɨɩɪɚɜɤɚɦɢ. ɇɚɩɪɢɦɟɪ, ɜɥɢɹɧɢɟ gg → gγ ɧɟ ɩɪɟɜɵɲɚɸɬ 1%. ɋɟɱɟɧɢɹ ɪɟɚɤɰɢɢ ɪɪ → γX ɩɪɢ ɤɟɧɨɜɫɤɨɣ ɩɟɪɟɦɟɧɧɨɣ 2 ⋅10 −6 s =1,96 Ɍɷȼ ɡɚɜɢɫɹɬ ɨɬ ɮɭɧɤɰɢɣ ɪɚɫɩɪɟɞɟɥɟɧɢɹ ɩɚɪɬɨɧɨɜ ɩɪɢ ɡɧɚɱɟɧɢɹɯ ɛɶɟɪs ɞɨ 14 Ɍɷȼ ɷɬɚ ɨɛɥɚɫɬɶ ɪɚɫɲɢɪɹɟɬɫɹ ɞɨ ɯa 5 ⋅10 −8. GɯG1. ɋ ɪɨɫɬɨɦ ɷɧɟɪɝɢɢ 20 «Â³ñíèê Õàðê³âñüêîãî óí³âåðñèòåòó», ¹ 845, 2009 Â.Â. Êîòëÿð, Í.È. Ìàñëîâ... ɉɪɨɜɟɞɟɧɧɵɣ ɚɧɚɥɢɡ ɞɟɦɨɧɫɬɪɢɪɭɟɬ, ɱɬɨ ɨɫɧɨɜɧɵɦ ɢɫɬɨɱɧɢɤɨɦ ɮɨɧɚ ɜ ɪɨɠɞɟɧɢɢ ɦɝɧɨɜɟɧɧɵɯ ɮɨɬɨɧɨɜ ɹɜɥɹɸɬɫɹ ɪɚɫɩɚɞɵ π°–ɦɟɡɨɧɨɜ. Ⱦɥɹ ɩɨɩɟɪɟɱɧɵɯ ɢɦɩɭɥɶɫɨɜ 5 Ƚɷȼ/ɫ < ɪɌ < 100 Ƚɷȼ/ɫ ɢ ɩɫɟɜɞɨɛɵɫɬɪɨɬ |η|<10 ɫɩɟɤɬɪɵ ɦɝɧɨɜɟɧɧɵɯ ɮɨɬɨɧɨɜ ɩɪɟɜɵɲɚɸɬ ɛɨɥɟɟ ɱɟɦ ɜ 103 ɪɚɡ ɫɩɟɤɬɪɵ ɮɨɧɨɜɵɯ ɮɨɬɨɧɨɜ, ɤɨɬɨɪɵɟ ɭɱɢɬɵɜɚɸɬɫɹ ɜ ɨɤɪɟɫɬɧɨɫɬɢ ∆ϕ = 5,2 ⋅10 −3 ɢ ∆η = 0,5 ɢɦɩɭɥɶɫɚ ɢɞɟɧɬɢɮɢɰɢɪɨɜɚɧɧɨɝɨ ɝɚɦɦɚ–ɤɜɚɧɬɚ. Ɉɞɢɧ ɢɡ ɚɜɬɨɪɨɜ (ȼ.ȼ.Ʉ.) ɜɵɪɚɠɚɟɬ ɛɥɚɝɨɞɚɪɧɨɫɬɶ Ⱥ.Ⱥ. Ȼɨɪɢɫɟɧɤɨ ɡɚ ɫɨɞɟɣɫɬɜɢɟ ɜ ɩɪɨɜɟɞɟɧɢɢ ɱɢɫɥɟɧɧɵɯ ɪɚɫɱɟɬɨɜ. 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. ɋɉɂɋɈɄ ɅɂɌȿɊȺɌɍɊɕ Aurenche P., et al. Gluon content of the nucleon probed with real and virtual photons // Phys. Rev. D. – 1989. – Vol.39. – P.3275–3286. Conesa G., et al. Identification of photon-tagged jets in the ALICE experiment // Nucl. Instrum. Meth. A. – 2008. –Vol.585. –P.28–39. Kumar A., et al. Study of parton kT smearing effects in direct photon production at the Fermilab Tevatron // Phys. Rev. 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J–hadron correlation measurements to study jets fragmentation with ALICE at LHC // Eur. Phys. J. C. – 2008. – Vol. 57. – P.613-619. Conesa Balbastre G. Particle isolation in PYTHIA // Proc. of ALICE Physics week (01 April 2008). Physics Working Group 4: photons and high pt. – 22p. PROMPT PHOTONS IN PROTON–PROTON SCATTERING AT THE LARGE HADRON COLLIDER V.V. Kotlyar*, N.I. Maslov*, A.O. Shcheglova** * National Science Center «Kharkov Institute of Physics and Technology», Akademichna 1, 61108 Kharkov, Ukraine E-mail: kotlyarv@kipt.kharkov.ua ** V.N. Karazin Kharkov National University, Svoboda Sq. 4, Kharkov 61077, Ukraine Prompt photon production in pp ‘ JX is studied taking advantage of event generator Pythia. Calculations are carried out at energies 2…14 ɌeV in the area of transverse momenta ɪɌ < 200 GeV/ɫ and pseudorapidities |K|<10. Relative role of mechanisms of pp ‘ JX is investigated both in leading order of perturbative QCD and with inclusion of next–to–leading order processes. Spectra of isolated photons to be measured with the help of photon spectrometer PHOS in ALICE experiment at the LHC are discussed. Computed cross sections are compared with results obtained by other authors and with experimental data. KEY WORDS: event generator Pythia, prompt photons, proton–proton scattering, photon spectrometer PHOS, ALICE experiment, large hadron collider