COMEX5 COMEX5 M ARIOLA K-G I NTRODUCTION E LECTROMAGNETIC EPA T HEORY EXCITATION OF NUCLEI F ORMALISM F ORM FACTOR P HOTON - INDUCED IN PHOTOABSORPTION REACTIONS EXCITATION OF NUCLEI AND IN UPC P HOTOABSORPTION CROSS SECTION H AUSER -F ESHBACH E XCITATION FUNCTIONS EM EXCITATIONS IN UPC S Mariola Kłusek-Gawenda ZDC S INGLE EXCITATION M UTUAL EXCITATION Niewodnicza´ nski Institute of Nuclear Physics Polish Academy of Sciences, P ARTICLE PRODUCTION + NEUTRONS EMISSION Kraków, Poland C ONCLUSION M ARIOLA K-G (K RAKÓW ) COMEX5 K RAKÓW , 14-18.09.2015 1 / 23
I NTRODUCTION COMEX5 E LECTRO M AGNETIC E XCITATION OF N UCLEI M ARIOLA K-G ◮ Heavy ion collision → photons fluxes [ v ≈ c ] I NTRODUCTION ◮ Photon → nucleus excitation EPA A ∗ A ∗ A 1 A 1 T HEORY 1 1 F ORMALISM F ORM FACTOR P HOTON - INDUCED EXCITATION OF A ∗ A 2 A 2 A 2 2 NUCLEI ◮ De-excitation P HOTOABSORPTION CROSS SECTION H AUSER -F ESHBACH → system breakup E XCITATION FUNCTIONS → neutron emission EM EXCITATIONS IN UPC S A ∗ A 1 n A ∗ A 1 n 1 1 ZDC S INGLE EXCITATION M UTUAL EXCITATION A ∗ A 2 n P ARTICLE PRODUCTION + A 2 A 2 2 ◮ Meson production with neutron emission NEUTRONS EMISSION C ONCLUSION A ∗ A ∗ A 1 A 1 n n 1 1 X 1 X X 2 A 2 A 2 A 2 A 2 M ARIOLA K-G (K RAKÓW ) COMEX5 K RAKÓW , 14-18.09.2015 2 / 23
EPA T HEORY COMEX5 E QUIVALENT P HOTON A PPROXIMATION M ARIOLA K-G I NTRODUCTION The strong electromagnetic EPA T HEORY field is a source of photons F ORMALISM R 1 F ORM FACTOR that can induce P HOTON - INDUCED electromagnetic reactions EXCITATION OF NUCLEI in ion-ion collisions. P HOTOABSORPTION CROSS SECTION H AUSER -F ESHBACH b E XCITATION FUNCTIONS U LTRA P ERIPHERAL C OLLISIONS EM EXCITATIONS IN UPC S ZDC b > R min = R 1 + R 2 S INGLE EXCITATION M UTUAL EXCITATION R 2 P ARTICLE PRODUCTION + NEUTRONS EMISSION C ONCLUSION b 1 b 2 b M ARIOLA K-G (K RAKÓW ) COMEX5 K RAKÓW , 14-18.09.2015 3 / 23
EPA F ORMALISM COMEX5 EM EXCITATION IN UPC M ARIOLA K-G A 1 A 1 I NTRODUCTION Single E EPA T HEORY 2 ( E ∗ = E ) A ∗ A 2 F ORMALISM d 2 b P surv ( b ) P exc � � � F ORM FACTOR σ A 1 A 2 → A 1 A ∗ = A 2 ( b ) 2 P HOTON - INDUCED A ∗ 1 ( E ∗ A 1 1 = E 1 ) EXCITATION OF NUCLEI E 1 Mutual P HOTOABSORPTION CROSS SECTION E 2 H AUSER -F ESHBACH E XCITATION FUNCTIONS A ∗ 2 ( E ∗ A 2 2 = E 2 ) d 2 b P surv ( b ) P exc A 2 ( b ) P exc � � � EM EXCITATIONS σ A 1 A 2 → A ∗ 1 A ∗ = A 1 ( b ) 2 IN UPC S ZDC S INGLE EXCITATION M UTUAL EXCITATION P surv ( b ) ∼ θ ( | b | − ( R 1 + R 2 )) P ARTICLE PRODUCTION + NEUTRONS EMISSION P exc � � C ONCLUSION A 2 ( b ) = n A 2 ( b ) exp − n A 2 ( b ) ∞ � d E N A 1 ( E , b ) σ tot ( γ A 2 ; E ) n A 2 ( b ) = E min M ARIOLA K-G (K RAKÓW ) COMEX5 K RAKÓW , 14-18.09.2015 4 / 23
EPA F ORMALISM COMEX5 F ORM FACTOR 2 � � 2 + u 2 � ( Eb � γ ) M ARIOLA K-G � � F � � b 2 N ( E , b ) = Z 2 α em � � u 2 J 1 ( u ) � I NTRODUCTION � � π 2 � 2 � Eb + u 2 � � EPA γ � � T HEORY � � F ORMALISM ◮ R EALISTIC ◮ M ONOPOLE F ORM FACTOR P HOTON - INDUCED Λ 2 F ( q ) = 4 π � EXCITATION OF ρ ( r ) sin ( qr ) rdr F ( q ) = q Λ 2 + q 2 NUCLEI P HOTOABSORPTION CROSS � SECTION 6 Λ = Form factor 1 197 H AUSER -F ESHBACH Au < r 2 > Realistic E XCITATION FUNCTIONS 208 Pb Monopole 197 Au ⇒ � < r 2 > = 5 . 3 fm, ◮ EM EXCITATIONS -1 10 IN UPC S Λ = 91 MeV, 208 Pb ⇒ � < r 2 > = 5 . 5 fm, ZDC ◮ -2 10 S INGLE EXCITATION |F(q)| Λ = 88 MeV. M UTUAL EXCITATION In the literature: P ARTICLE PRODUCTION + -3 10 NEUTRONS EMISSION Λ = ( 80 − 90 ) GeV C ONCLUSION -4 10 ◮ P OINT -L IKE -5 10 0 0.2 0.4 0.6 0.8 1 F ( q ) = 1 q [GeV] M ARIOLA K-G (K RAKÓW ) COMEX5 K RAKÓW , 14-18.09.2015 5 / 23
EPA F ORMALISM COMEX5 M ARIOLA K-G AuAu → AuAu µ + µ − I NTRODUCTION EPA 7 T HEORY 10 1 F s = 200 GeV realistic s = 200 GeV F ORMALISM NN NN 0.9 )/db [nb/fm] F F ORM FACTOR monopole 0.8 P HOTON - INDUCED ) monopole EXCITATION OF 0.7 6 10 NUCLEI - 0.6 (F µ P HOTOABSORPTION CROSS + σ µ SECTION )/d AuAu 0.5 H AUSER -F ESHBACH realistic 0.4 E XCITATION FUNCTIONS → 5 10 (AuAu (F 0.3 EM EXCITATIONS σ IN UPC S d 0.2 σ ZDC d 0.1 S INGLE EXCITATION 0 M UTUAL EXCITATION 0 200 400 600 800 0 200 400 600 800 P ARTICLE PRODUCTION + b [fm] b [fm] NEUTRONS EMISSION C ONCLUSION M ARIOLA K-G (K RAKÓW ) COMEX5 K RAKÓW , 14-18.09.2015 6 / 23
P HOTON - INDUCED EXCITATION OF NUCLEI P HOTOABSORPTION CROSS SECTION COMEX5 γ 197 Au & γ 208 Pb M ARIOLA K-G 3 3 10 10 I NTRODUCTION EPA Au) [mb] Pb) [mb] T HEORY 10 2 10 2 F ORMALISM F ORM FACTOR 197 208 γ γ ( ( P HOTON - INDUCED σ σ EXCITATION OF NUCLEI 10 10 P HOTOABSORPTION CROSS SECTION 2 3 4 5 2 3 4 5 10 10 10 10 10 10 10 10 10 10 H AUSER -F ESHBACH E [MeV] E [MeV] E XCITATION FUNCTIONS EM EXCITATIONS IN UPC S σ γ A = σ GDR + σ QD + σ nucleon res . + σ nucleon cont . ZDC S INGLE EXCITATION 1. E γ < 40 MeV - σ GDR M UTUAL EXCITATION P ARTICLE PRODUCTION + 2. E γ = ( 40 − 100 ) MeV - σ QD NEUTRONS EMISSION C ONCLUSION 3. E γ = ( 100 − 1000 ) MeV - σ nucleon resonances 4. E γ = ( 1 − 8 ) GeV - σ low − energy nucleon continuum 5. E γ > 8 GeV - σ high − energy nucleon continuum M ARIOLA K-G (K RAKÓW ) COMEX5 K RAKÓW , 14-18.09.2015 7 / 23
P HOTON - INDUCED EXCITATION OF NUCLEI H AUSER -F ESHBACH COMEX5 P ROBABILITY OF NEUTRON MULTIPLICITY M ARIOLA K-G I NTRODUCTION 197 208 EPA Au Pb 1 0n 1 0n T HEORY 1n 1n F ORMALISM 2n 2n F ORM FACTOR 3n 3n 4n 4n P HOTON - INDUCED -1 5n -1 5n 10 10 EXCITATION OF (E*) 6n (E*) 6n NUCLEI 7n 7n k k P 8n P 8n P HOTOABSORPTION CROSS SECTION 9n 9n 10n 10n H AUSER -F ESHBACH -2 -2 10 10 fit fit E XCITATION FUNCTIONS ___ ___ EM EXCITATIONS sum: sum: IN UPC S GEMINI GEMINI fit fit ZDC -3 -3 10 10 20 40 60 80 100 20 40 60 80 100 S INGLE EXCITATION E* [MeV] E* [MeV] M UTUAL EXCITATION P ARTICLE PRODUCTION + NEUTRONS EMISSION C ONCLUSION GEMINI++ evaporation process is described by the Hauser-Feshbach formalism More details �→ back-up slides M ARIOLA K-G (K RAKÓW ) COMEX5 K RAKÓW , 14-18.09.2015 8 / 23
P HOTON - INDUCED EXCITATION OF NUCLEI E XCITATION FUNCTIONS COMEX5 γ A Au / Pb → 1 n ( A − 1 ) Au / Pb M ARIOLA K-G I NTRODUCTION EPA T HEORY F ORMALISM F ORM FACTOR 800 800 P HOTON - INDUCED ( ,n) ( ,n) γ γ EXCITATION OF 2007 1972 700 700 NUCLEI 2010 1978 Au) [mb] Pb) [mb] 2011 1985 P HOTOABSORPTION CROSS 600 600 2011 1985 SECTION ( ,n)+( ,n+p) 1991 H AUSER -F ESHBACH γ γ 500 500 1962 1993 E XCITATION FUNCTIONS 196 207 1970 ( ,n)+( ,n+p) γ γ 1n 1n 400 400 EM EXCITATIONS 1987 1964 → → IN UPC S 2003 1970 Au Pb 300 300 ZDC 2010 197 208 S INGLE EXCITATION γ γ 200 200 ( ( σ σ M UTUAL EXCITATION P ARTICLE PRODUCTION + 100 100 NEUTRONS EMISSION C ONCLUSION 5 10 15 20 25 30 5 10 15 20 25 30 E [MeV] E [MeV] γ γ M ARIOLA K-G (K RAKÓW ) COMEX5 K RAKÓW , 14-18.09.2015 9 / 23
P HOTON - INDUCED EXCITATION OF NUCLEI E XCITATION FUNCTIONS COMEX5 γ A Au / Pb → 2 n ( A − 2 ) Au / Pb M ARIOLA K-G I NTRODUCTION EPA T HEORY F ORMALISM F ORM FACTOR 250 250 P HOTON - INDUCED ( ,2n) ( ,2n) γ γ EXCITATION OF 1987 2003 NUCLEI 2003 2003 200 200 Au) [mb] Pb) [mb] 2003 ( γ ,2n)+( γ ,2n+p) P HOTOABSORPTION CROSS ( ,2n)+( ,2n+p) 1964 SECTION γ γ 1962 1970 H AUSER -F ESHBACH 150 150 1970 E XCITATION FUNCTIONS 195 206 1987 2n 2n EM EXCITATIONS → → IN UPC S 100 100 Au Pb ZDC 197 208 S INGLE EXCITATION γ γ ( ( σ σ M UTUAL EXCITATION 50 50 P ARTICLE PRODUCTION + NEUTRONS EMISSION C ONCLUSION 10 15 20 25 30 35 10 15 20 25 30 35 E [MeV] E [MeV] γ γ M ARIOLA K-G (K RAKÓW ) COMEX5 K RAKÓW , 14-18.09.2015 10 / 23
P HOTON - INDUCED EXCITATION OF NUCLEI E XCITATION FUNCTIONS COMEX5 γ A Au / Pb → 3 n ( A − 3 ) Au / Pb M ARIOLA K-G I NTRODUCTION EPA T HEORY F ORMALISM F ORM FACTOR 30 30 P HOTON - INDUCED ( ,3n) ( ,3n) γ γ EXCITATION OF 1970 1970 NUCLEI 25 25 Au) [mb] Pb) [mb] P HOTOABSORPTION CROSS SECTION 20 20 H AUSER -F ESHBACH E XCITATION FUNCTIONS 194 205 3n 3n EM EXCITATIONS 15 15 → → IN UPC S Au Pb ZDC 197 208 10 10 S INGLE EXCITATION γ γ ( ( σ σ M UTUAL EXCITATION P ARTICLE PRODUCTION + 5 5 NEUTRONS EMISSION C ONCLUSION 20 25 30 35 40 45 20 25 30 35 40 45 E [MeV] E [MeV] γ γ M ARIOLA K-G (K RAKÓW ) COMEX5 K RAKÓW , 14-18.09.2015 11 / 23
EM EXCITATIONS IN UPC S ZDC COMEX5 M ARIOLA K-G I NTRODUCTION EPA T HEORY F ORMALISM F ORM FACTOR P HOTON - INDUCED EXCITATION OF NUCLEI P HOTOABSORPTION CROSS SECTION H AUSER -F ESHBACH E XCITATION FUNCTIONS EM EXCITATIONS IN UPC S ZDC S INGLE EXCITATION FIG. ZNA energy spectrum requiring signal over threshold M UTUAL EXCITATION P ARTICLE PRODUCTION + in ZNA but not in ZNC, rejecting thus neutron emission on NEUTRONS EMISSION C ONCLUSION the opposite side. The dashed lines represent the single fits of the different peaks (1n, 2n,...), while the continuous line is the sum of all the contributions. P . Cortese, International Conference on New Frontiers in Physics 2012 M ARIOLA K-G (K RAKÓW ) COMEX5 K RAKÓW , 14-18.09.2015 12 / 23
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