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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

slide-1
SLIDE 1

COMEX5 MARIOLA K-G INTRODUCTION EPA

THEORY FORMALISM FORM FACTOR

PHOTON-INDUCED

EXCITATION OF NUCLEI

PHOTOABSORPTION CROSS

SECTION

HAUSER-FESHBACH EXCITATION FUNCTIONS

EM EXCITATIONS

IN UPCS

ZDC SINGLE EXCITATION MUTUAL EXCITATION PARTICLE PRODUCTION +

NEUTRONS EMISSION

CONCLUSION

COMEX5

ELECTROMAGNETIC

EXCITATION OF NUCLEI IN PHOTOABSORPTION REACTIONS AND IN UPC

Mariola Kłusek-Gawenda

Niewodnicza´ nski Institute of Nuclear Physics Polish Academy of Sciences, Kraków, Poland

MARIOLA K-G (KRAKÓW) COMEX5 KRAKÓW, 14-18.09.2015 1 / 23

slide-2
SLIDE 2

COMEX5 MARIOLA K-G INTRODUCTION EPA

THEORY FORMALISM FORM FACTOR

PHOTON-INDUCED

EXCITATION OF NUCLEI

PHOTOABSORPTION CROSS

SECTION

HAUSER-FESHBACH EXCITATION FUNCTIONS

EM EXCITATIONS

IN UPCS

ZDC SINGLE EXCITATION MUTUAL EXCITATION PARTICLE PRODUCTION +

NEUTRONS EMISSION

CONCLUSION INTRODUCTION

ELECTROMAGNETIC EXCITATION OF NUCLEI

◮ Heavy ion collision → photons fluxes

[v ≈ c]

◮ Photon → nucleus excitation

A1 A2 A2 A∗

1

A1 A2 A∗

2

A∗

1

◮ De-excitation

→ system breakup → neutron emission

A1 A2 A2 A∗

1

n A1 A2 A∗

2

A∗

1

n n

◮ Meson production with neutron emission

A1 A2 A2 A∗

1

n X X1 A1 A2 A∗

1

A2 X2 n

MARIOLA K-G (KRAKÓW) COMEX5 KRAKÓW, 14-18.09.2015 2 / 23

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SLIDE 3

COMEX5 MARIOLA K-G INTRODUCTION EPA

THEORY FORMALISM FORM FACTOR

PHOTON-INDUCED

EXCITATION OF NUCLEI

PHOTOABSORPTION CROSS

SECTION

HAUSER-FESHBACH EXCITATION FUNCTIONS

EM EXCITATIONS

IN UPCS

ZDC SINGLE EXCITATION MUTUAL EXCITATION PARTICLE PRODUCTION +

NEUTRONS EMISSION

CONCLUSION EPA THEORY

EQUIVALENT PHOTON APPROXIMATION

b

R1 R2

The strong electromagnetic field is a source of photons that can induce electromagnetic reactions in ion-ion collisions.

ULTRAPERIPHERAL COLLISIONS

b > Rmin = R1 + R2

b1 b2 b

MARIOLA K-G (KRAKÓW) COMEX5 KRAKÓW, 14-18.09.2015 3 / 23

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SLIDE 4

COMEX5 MARIOLA K-G INTRODUCTION EPA

THEORY FORMALISM FORM FACTOR

PHOTON-INDUCED

EXCITATION OF NUCLEI

PHOTOABSORPTION CROSS

SECTION

HAUSER-FESHBACH EXCITATION FUNCTIONS

EM EXCITATIONS

IN UPCS

ZDC SINGLE EXCITATION MUTUAL EXCITATION PARTICLE PRODUCTION +

NEUTRONS EMISSION

CONCLUSION EPA FORMALISM

EM EXCITATION IN UPC

Single

A1 A2 A1 A∗

2(E∗ = E)

E

σ

  • A1A2 → A1A∗

2

  • =
  • d2b Psurv (b)Pexc

A2 (b)

Mutual

A1 A2 A∗

1(E∗ 1 = E1)

A∗

2(E∗ 2 = E2)

E1 E2

σ

  • A1A2 → A∗

1A∗ 2

  • =
  • d2b Psurv (b)Pexc

A2 (b)Pexc A1 (b)

Psurv (b) ∼ θ (|b| − (R1 + R2)) Pexc

A2 (b) = nA2 (b) exp

  • −nA2 (b)
  • nA2 (b) =

∞

  • Emin

dE NA1 (E, b)σtot (γA2; E)

MARIOLA K-G (KRAKÓW) COMEX5 KRAKÓW, 14-18.09.2015 4 / 23

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SLIDE 5

COMEX5 MARIOLA K-G INTRODUCTION EPA

THEORY FORMALISM FORM FACTOR

PHOTON-INDUCED

EXCITATION OF NUCLEI

PHOTOABSORPTION CROSS

SECTION

HAUSER-FESHBACH EXCITATION FUNCTIONS

EM EXCITATIONS

IN UPCS

ZDC SINGLE EXCITATION MUTUAL EXCITATION PARTICLE PRODUCTION +

NEUTRONS EMISSION

CONCLUSION EPA FORMALISM

FORM FACTOR

N(E, b) = Z 2αem

π2

  • u2J1 (u)

F ( Eb

γ ) 2+u2 b2

  • Eb

γ

2 +u2

  • 2

◮ REALISTIC

F(q) = 4π

q

  • ρ (r) sin (qr) rdr

q [GeV]

0.2 0.4 0.6 0.8 1

|F(q)|

  • 5

10

  • 4

10

  • 3

10

  • 2

10

  • 1

10 1

Au

197

Pb

208

Form factor Realistic Monopole

◮ MONOPOLE

F(q) =

Λ2 Λ2+q2

Λ =

  • 6

<r 2> ◮

197Au ⇒

  • < r2 > = 5.3 fm,

Λ = 91 MeV,

◮

208Pb ⇒

  • < r2 > = 5.5 fm,

Λ = 88 MeV.

In the literature: Λ = (80 − 90) GeV

◮ POINT-LIKE

F(q) = 1

MARIOLA K-G (KRAKÓW) COMEX5 KRAKÓW, 14-18.09.2015 5 / 23

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SLIDE 6

COMEX5 MARIOLA K-G INTRODUCTION EPA

THEORY FORMALISM FORM FACTOR

PHOTON-INDUCED

EXCITATION OF NUCLEI

PHOTOABSORPTION CROSS

SECTION

HAUSER-FESHBACH EXCITATION FUNCTIONS

EM EXCITATIONS

IN UPCS

ZDC SINGLE EXCITATION MUTUAL EXCITATION PARTICLE PRODUCTION +

NEUTRONS EMISSION

CONCLUSION EPA FORMALISM

AuAu → AuAu µ+µ−

b [fm]

200 400 600 800

)/db [nb/fm]

  • µ

+

µ AuAu → (AuAu σ d

5

10

6

10

7

10

realistic

F

monopole

F = 200 GeV

NN

s

b [fm]

200 400 600 800

)

monopole

(F σ )/d

realistic

(F σ d

0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 = 200 GeV

NN

s

MARIOLA K-G (KRAKÓW) COMEX5 KRAKÓW, 14-18.09.2015 6 / 23

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SLIDE 7

COMEX5 MARIOLA K-G INTRODUCTION EPA

THEORY FORMALISM FORM FACTOR

PHOTON-INDUCED

EXCITATION OF NUCLEI

PHOTOABSORPTION CROSS

SECTION

HAUSER-FESHBACH EXCITATION FUNCTIONS

EM EXCITATIONS

IN UPCS

ZDC SINGLE EXCITATION MUTUAL EXCITATION PARTICLE PRODUCTION +

NEUTRONS EMISSION

CONCLUSION PHOTON-INDUCED EXCITATION OF NUCLEI PHOTOABSORPTION CROSS SECTION

γ197Au & γ208Pb

E [MeV] 10

2

10

3

10

4

10

5

10 Au) [mb]

197

γ ( σ 10

2

10

3

10 E [MeV] 10

2

10

3

10

4

10

5

10 Pb) [mb]

208

γ ( σ 10

2

10

3

10

σγA = σGDR + σQD + σnucleon res. + σnucleon cont.

  • 1. Eγ < 40 MeV - σGDR
  • 2. Eγ = (40 − 100) MeV - σQD
  • 3. Eγ = (100 − 1000) MeV - σnucleon resonances
  • 4. Eγ = (1 − 8) GeV - σlow−energy

nucleon continuum

  • 5. Eγ > 8 GeV - σhigh−energy

nucleon continuum

MARIOLA K-G (KRAKÓW) COMEX5 KRAKÓW, 14-18.09.2015 7 / 23

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SLIDE 8

COMEX5 MARIOLA K-G INTRODUCTION EPA

THEORY FORMALISM FORM FACTOR

PHOTON-INDUCED

EXCITATION OF NUCLEI

PHOTOABSORPTION CROSS

SECTION

HAUSER-FESHBACH EXCITATION FUNCTIONS

EM EXCITATIONS

IN UPCS

ZDC SINGLE EXCITATION MUTUAL EXCITATION PARTICLE PRODUCTION +

NEUTRONS EMISSION

CONCLUSION PHOTON-INDUCED EXCITATION OF NUCLEI HAUSER-FESHBACH

PROBABILITY OF NEUTRON MULTIPLICITY

E* [MeV]

20 40 60 80 100

(E*)

k

P

  • 3

10

  • 2

10

  • 1

10 1

Au

197

0n 1n 2n 3n 4n 5n 6n 7n 8n 9n 10n fit ___ sum:

GEMINI

fit

E* [MeV]

20 40 60 80 100

(E*)

k

P

  • 3

10

  • 2

10

  • 1

10 1

Pb

208

0n 1n 2n 3n 4n 5n 6n 7n 8n 9n 10n fit ___ sum:

GEMINI

fit

GEMINI++ evaporation process is described by the Hauser-Feshbach formalism

More details → back-up slides MARIOLA K-G (KRAKÓW) COMEX5 KRAKÓW, 14-18.09.2015 8 / 23

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SLIDE 9

COMEX5 MARIOLA K-G INTRODUCTION EPA

THEORY FORMALISM FORM FACTOR

PHOTON-INDUCED

EXCITATION OF NUCLEI

PHOTOABSORPTION CROSS

SECTION

HAUSER-FESHBACH EXCITATION FUNCTIONS

EM EXCITATIONS

IN UPCS

ZDC SINGLE EXCITATION MUTUAL EXCITATION PARTICLE PRODUCTION +

NEUTRONS EMISSION

CONCLUSION PHOTON-INDUCED EXCITATION OF NUCLEI EXCITATION FUNCTIONS

γAAu/Pb → 1n(A−1)Au/Pb

[MeV]

γ

E

5 10 15 20 25 30

Au) [mb]

196

1n → Au

197

γ ( σ

100 200 300 400 500 600 700 800

,n) γ ( 2007 2010 2011 2011 ,n+p) γ ,n)+( γ ( 1962 1970 1987 2003 2010

[MeV]

γ

E

5 10 15 20 25 30

Pb) [mb]

207

1n → Pb

208

γ ( σ

100 200 300 400 500 600 700 800

,n) γ ( 1972 1978 1985 1985 1991 1993 ,n+p) γ ,n)+( γ ( 1964 1970

MARIOLA K-G (KRAKÓW) COMEX5 KRAKÓW, 14-18.09.2015 9 / 23

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SLIDE 10

COMEX5 MARIOLA K-G INTRODUCTION EPA

THEORY FORMALISM FORM FACTOR

PHOTON-INDUCED

EXCITATION OF NUCLEI

PHOTOABSORPTION CROSS

SECTION

HAUSER-FESHBACH EXCITATION FUNCTIONS

EM EXCITATIONS

IN UPCS

ZDC SINGLE EXCITATION MUTUAL EXCITATION PARTICLE PRODUCTION +

NEUTRONS EMISSION

CONCLUSION PHOTON-INDUCED EXCITATION OF NUCLEI EXCITATION FUNCTIONS

γAAu/Pb → 2n(A−2)Au/Pb

[MeV]

γ

E

10 15 20 25 30 35

Au) [mb]

195

2n → Au

197

γ ( σ

50 100 150 200 250

,2n) γ ( 1987 2003 2003 ,2n+p) γ ,2n)+( γ ( 1962 1970 1987

[MeV]

γ

E

10 15 20 25 30 35

Pb) [mb]

206

2n → Pb

208

γ ( σ

50 100 150 200 250

,2n) γ ( 2003 2003 ,2n+p) γ ,2n)+( γ ( 1964 1970

MARIOLA K-G (KRAKÓW) COMEX5 KRAKÓW, 14-18.09.2015 10 / 23

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SLIDE 11

COMEX5 MARIOLA K-G INTRODUCTION EPA

THEORY FORMALISM FORM FACTOR

PHOTON-INDUCED

EXCITATION OF NUCLEI

PHOTOABSORPTION CROSS

SECTION

HAUSER-FESHBACH EXCITATION FUNCTIONS

EM EXCITATIONS

IN UPCS

ZDC SINGLE EXCITATION MUTUAL EXCITATION PARTICLE PRODUCTION +

NEUTRONS EMISSION

CONCLUSION PHOTON-INDUCED EXCITATION OF NUCLEI EXCITATION FUNCTIONS

γAAu/Pb → 3n(A−3)Au/Pb

[MeV]

γ

E

20 25 30 35 40 45

Au) [mb]

194

3n → Au

197

γ ( σ

5 10 15 20 25 30

,3n) γ ( 1970

[MeV]

γ

E

20 25 30 35 40 45

Pb) [mb]

205

3n → Pb

208

γ ( σ

5 10 15 20 25 30

,3n) γ ( 1970

MARIOLA K-G (KRAKÓW) COMEX5 KRAKÓW, 14-18.09.2015 11 / 23

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SLIDE 12

COMEX5 MARIOLA K-G INTRODUCTION EPA

THEORY FORMALISM FORM FACTOR

PHOTON-INDUCED

EXCITATION OF NUCLEI

PHOTOABSORPTION CROSS

SECTION

HAUSER-FESHBACH EXCITATION FUNCTIONS

EM EXCITATIONS

IN UPCS

ZDC SINGLE EXCITATION MUTUAL EXCITATION PARTICLE PRODUCTION +

NEUTRONS EMISSION

CONCLUSION EM EXCITATIONS IN UPCS ZDC P . Cortese, International Conference on New Frontiers in Physics 2012

  • FIG. ZNA energy spectrum requiring signal over threshold

in ZNA but not in ZNC, rejecting thus neutron emission on 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. MARIOLA K-G (KRAKÓW) COMEX5 KRAKÓW, 14-18.09.2015 12 / 23

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SLIDE 13

COMEX5 MARIOLA K-G INTRODUCTION EPA

THEORY FORMALISM FORM FACTOR

PHOTON-INDUCED

EXCITATION OF NUCLEI

PHOTOABSORPTION CROSS

SECTION

HAUSER-FESHBACH EXCITATION FUNCTIONS

EM EXCITATIONS

IN UPCS

ZDC SINGLE EXCITATION MUTUAL EXCITATION PARTICLE PRODUCTION +

NEUTRONS EMISSION

CONCLUSION EM EXCITATIONS IN UPCS SINGLE EXCITATION

SINGLE EXCITATION IN UPC

Au+Au @ √sNN = 130 GeV Pb+Pb @ √sNN = 2.76 TeV

kN

2 4 6

AuAu*) [b] → (AuAu σ

20 40 60 80 100

  • urs

= 130 GeV

NN

s

kN

2 4 6

PbPb*) [b] → (PbPb σ

20 40 60 80 100

  • urs

ALICE = 2.76 TeV

NN

s

◮ given multiplicity of neutrons ◮ single-nucleus, single-photon excitation 2n 1n

ALICE= (22.5 ± 0.5 (stat) ±0.9 (syst))%

  • urs= 21.6%

MARIOLA K-G (KRAKÓW) COMEX5 KRAKÓW, 14-18.09.2015 13 / 23

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SLIDE 14

COMEX5 MARIOLA K-G INTRODUCTION EPA

THEORY FORMALISM FORM FACTOR

PHOTON-INDUCED

EXCITATION OF NUCLEI

PHOTOABSORPTION CROSS

SECTION

HAUSER-FESHBACH EXCITATION FUNCTIONS

EM EXCITATIONS

IN UPCS

ZDC SINGLE EXCITATION MUTUAL EXCITATION PARTICLE PRODUCTION +

NEUTRONS EMISSION

CONCLUSION EM EXCITATIONS IN UPCS SINGLE EXCITATION

SINGLE EXCITATION IN UPC

[GeV]

NN

s

10

2

10

3

10

AuAu*) [b] → (AuAu

EMD

σ

1 10

2

10

3

10

SPS total 1n 2n

[GeV]

NN

s

10

2

10

3

10

PbPb*) [b] → (PbPb

EMD

σ

1 10

2

10

3

10

SPS ALICE total 1n 2n

MARIOLA K-G (KRAKÓW) COMEX5 KRAKÓW, 14-18.09.2015 14 / 23

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SLIDE 15

COMEX5 MARIOLA K-G INTRODUCTION EPA

THEORY FORMALISM FORM FACTOR

PHOTON-INDUCED

EXCITATION OF NUCLEI

PHOTOABSORPTION CROSS

SECTION

HAUSER-FESHBACH EXCITATION FUNCTIONS

EM EXCITATIONS

IN UPCS

ZDC SINGLE EXCITATION MUTUAL EXCITATION PARTICLE PRODUCTION +

NEUTRONS EMISSION

CONCLUSION EM EXCITATIONS IN UPCS MUTUAL EXCITATION

MUTUAL EXCITATIONS

Cross section (in barns) for Au+Au @ √sNN = 130 GeV

1n 2n 3n 4n 5n 6n 1n 0.5082 0.1002 0.0195 0.0137 0.0096 0.0091 2n 0.1002 0.0198 0.0038 0.0027 0.0019 0.0018 3n 0.0195 0.0038 0.0007 0.0005 0.0004 0.0003 4n 0.0137 0.0027 0.0005 0.0004 0.0003 0.0002 5n 0.0096 0.0019 0.0004 0.0003 0.0002 0.0002 6n 0.0091 0.0018 0.0003 0.0002 0.0002 0.0002

  • 0.6603

0.1302 0.0252 0.0178 0.0126 0.0118

  • 0.8579

MARIOLA K-G (KRAKÓW) COMEX5 KRAKÓW, 14-18.09.2015 15 / 23

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SLIDE 16

COMEX5 MARIOLA K-G INTRODUCTION EPA

THEORY FORMALISM FORM FACTOR

PHOTON-INDUCED

EXCITATION OF NUCLEI

PHOTOABSORPTION CROSS

SECTION

HAUSER-FESHBACH EXCITATION FUNCTIONS

EM EXCITATIONS

IN UPCS

ZDC SINGLE EXCITATION MUTUAL EXCITATION PARTICLE PRODUCTION +

NEUTRONS EMISSION

CONCLUSION EM EXCITATIONS IN UPCS MUTUAL EXCITATION

MUTUAL EXCITATIONS

Cross section (in barns) for Au+Au @ √sNN = 130 GeV

1n 2n 3n 4n 5n 6n 1n 0.5082 0.1002 0.0195 0.0137 0.0096 0.0091 2n 0.1002 0.0198 0.0038 0.0027 0.0019 0.0018 3n 0.0195 0.0038 0.0007 0.0005 0.0004 0.0003 4n 0.0137 0.0027 0.0005 0.0004 0.0003 0.0002 5n 0.0096 0.0019 0.0004 0.0003 0.0002 0.0002 6n 0.0091 0.0018 0.0003 0.0002 0.0002 0.0002

  • 0.6603

0.1302 0.0252 0.0178 0.0126 0.0118

  • 0.8579

(kN,kN) Au*Au*) [b] → (AuAu σ

0.2 0.4 0.6 0.8 1 1.2 1.4 1.6

  • urs

PHENIX PHOBOS BRAHMS Baltz et al. Pshenichnov et al.

{

(1,X) σ

}

(1,1) σ

}

(2,X) σ

= 130 GeV

NN

s

MARIOLA K-G (KRAKÓW) COMEX5 KRAKÓW, 14-18.09.2015 16 / 23

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SLIDE 17

COMEX5 MARIOLA K-G INTRODUCTION EPA

THEORY FORMALISM FORM FACTOR

PHOTON-INDUCED

EXCITATION OF NUCLEI

PHOTOABSORPTION CROSS

SECTION

HAUSER-FESHBACH EXCITATION FUNCTIONS

EM EXCITATIONS

IN UPCS

ZDC SINGLE EXCITATION MUTUAL EXCITATION PARTICLE PRODUCTION +

NEUTRONS EMISSION

CONCLUSION EM EXCITATIONS IN UPCS MUTUAL EXCITATION

MUTUAL EXCITATIONS

NN

s

2

10

3

10

A*A*) [b] → (AA σ

3 3.5 4 4.5 5 5.5 6 6.5

  • urs

RHIC LHC

MARIOLA K-G (KRAKÓW) COMEX5 KRAKÓW, 14-18.09.2015 17 / 23

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SLIDE 18

COMEX5 MARIOLA K-G INTRODUCTION EPA

THEORY FORMALISM FORM FACTOR

PHOTON-INDUCED

EXCITATION OF NUCLEI

PHOTOABSORPTION CROSS

SECTION

HAUSER-FESHBACH EXCITATION FUNCTIONS

EM EXCITATIONS

IN UPCS

ZDC SINGLE EXCITATION MUTUAL EXCITATION PARTICLE PRODUCTION +

NEUTRONS EMISSION

CONCLUSION EM EXCITATIONS IN UPCS PARTICLE PRODUCTION + NEUTRONS EMISSION

APPLICATION TO EXCLUSIVE PROCESSES

A A V IP/IR A A A A V IP/IR A A

◮ AA → AAρ0(→ π+π−) ◮ AA → AAJ/ψ

A1 A2 A2 A1 X1 X2 γ γ

◮ AA → AAρ0ρ0(→ 4π) ◮ AA → AAl+l−

A A V IP/IR A A V IP/IR A A V IP/IR A A V IP/IR A A V IP/IR A A V IP/IR A A V IP/IR A A V IP/IR

◮ AA → AAρ0ρ0(→ π+π−π+π−) ◮ AA → AAJ/ψJ/ψ

MARIOLA K-G (KRAKÓW) COMEX5 KRAKÓW, 14-18.09.2015 18 / 23

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SLIDE 19

COMEX5 MARIOLA K-G INTRODUCTION EPA

THEORY FORMALISM FORM FACTOR

PHOTON-INDUCED

EXCITATION OF NUCLEI

PHOTOABSORPTION CROSS

SECTION

HAUSER-FESHBACH EXCITATION FUNCTIONS

EM EXCITATIONS

IN UPCS

ZDC SINGLE EXCITATION MUTUAL EXCITATION PARTICLE PRODUCTION +

NEUTRONS EMISSION

CONCLUSION EM EXCITATIONS IN UPCS PARTICLE PRODUCTION + NEUTRONS EMISSION

ρ0 PRODUCTION IN HEAVY ION UPC

WITH NUCLEAR EXCITATION

A1 A2 A∗

2

A∗

1

n ρ0 n

) [mb] ρ Au*Au* → (AuAu σ

100 200 300 400 500 600 700

STAR data

  • stat. error
  • syst. error
  • ur results

=130 GeV

NN

s

XnXn 0nXn 1n1n 0n0n total

very preliminary

MARIOLA K-G (KRAKÓW) COMEX5 KRAKÓW, 14-18.09.2015 19 / 23

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COMEX5 MARIOLA K-G INTRODUCTION EPA

THEORY FORMALISM FORM FACTOR

PHOTON-INDUCED

EXCITATION OF NUCLEI

PHOTOABSORPTION CROSS

SECTION

HAUSER-FESHBACH EXCITATION FUNCTIONS

EM EXCITATIONS

IN UPCS

ZDC SINGLE EXCITATION MUTUAL EXCITATION PARTICLE PRODUCTION +

NEUTRONS EMISSION

CONCLUSION CONCLUSION

CONCLUSIONS

◮ Impact parameter space approach ◮ Neutron emission ֋ Hauser-Feshbach formalism ◮ Good description of experimental data for

◮ the excitation functions for γ+197Au and γ+208Pb ◮ photoabsorption

+ giant resonances + quasi-deuteron + excitation of nucleon resonances + breakup of nucleon

◮ with fixed number of neutrons ◮ UPC heavy-ion collision (RHIC and LHC energy) ◮ single ◮ mutual excitations Reference:

  • M. K-G, M. Ciemała, W. Schäfer and A. Szczurek, Phys. Rev. C89 (2014) 054907,

”Electromagnetic excitation of nuclei and neutron evaporation in ultrarelativistic ultraperipheral heavy ion collisions”

◮ AuAu → Au∗Au∗ρ0(770) - theory & experiment

MARIOLA K-G (KRAKÓW) COMEX5 KRAKÓW, 14-18.09.2015 20 / 23

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SLIDE 21

COMEX5 MARIOLA K-G INTRODUCTION EPA

THEORY FORMALISM FORM FACTOR

PHOTON-INDUCED

EXCITATION OF NUCLEI

PHOTOABSORPTION CROSS

SECTION

HAUSER-FESHBACH EXCITATION FUNCTIONS

EM EXCITATIONS

IN UPCS

ZDC SINGLE EXCITATION MUTUAL EXCITATION PARTICLE PRODUCTION +

NEUTRONS EMISSION

CONCLUSION CONCLUSION

CONCLUSIONS

◮ not only UPC PbPb→PbPbJ/ψ

centrality [%]

20 40 60 80

b] µ [

Ψ J/

/dy σ d

50 100 150 200 250 300 350 ,b) ω (

(0)

N ,b) ω (

(1)

N ,b) ω (

(2)

N b2 b b1

(a) V

b2 b1 b

(b) V

Reference:

  • M. K-G and A. Szczurek,

arXiv: 1509.03173 [nucl-th], ”Photoproduction of J/ψ mesons in peripheral and semi-central heavy ion collisions”

ALICE data: talk given by Laura Massacrier at EDS Blois workshop, 29th June - 4th July 2015, Borgo, Corsica, France

MARIOLA K-G (KRAKÓW) COMEX5 KRAKÓW, 14-18.09.2015 21 / 23

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SLIDE 22

COMEX5 MARIOLA K-G INTRODUCTION EPA

THEORY FORMALISM FORM FACTOR

PHOTON-INDUCED

EXCITATION OF NUCLEI

PHOTOABSORPTION CROSS

SECTION

HAUSER-FESHBACH EXCITATION FUNCTIONS

EM EXCITATIONS

IN UPCS

ZDC SINGLE EXCITATION MUTUAL EXCITATION PARTICLE PRODUCTION +

NEUTRONS EMISSION

CONCLUSION CONCLUSION

Back-up slides

MARIOLA K-G (KRAKÓW) COMEX5 KRAKÓW, 14-18.09.2015 22 / 23

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SLIDE 23

COMEX5 MARIOLA K-G INTRODUCTION EPA

THEORY FORMALISM FORM FACTOR

PHOTON-INDUCED

EXCITATION OF NUCLEI

PHOTOABSORPTION CROSS

SECTION

HAUSER-FESHBACH EXCITATION FUNCTIONS

EM EXCITATIONS

IN UPCS

ZDC SINGLE EXCITATION MUTUAL EXCITATION PARTICLE PRODUCTION +

NEUTRONS EMISSION

CONCLUSION CONCLUSION

DECAYS OF EXCITED NUCLEAR SYSTEM

Γi = 1 2πρ(E∗, SCN)

  • dǫ

∞

  • Sd =0

SCN +Sd

  • J=|SCN −Sd |

J+Si

  • ℓ=|J−Si |

Tℓ(ǫ)ρ(E∗ − Bi − ǫ, Sd ) , (1) where Sd is the spin of the daughter nucleus, Si , J and ℓ are spin, total and angular momentum of the evaporated particle, ǫ, Bi are kinetic and separation energies, Tℓ is its transmission coefficient, ρ and ρCN are level densities of the daughter and compound nucleus, which can be calculated from the formula: ρ(E∗, S) ∝ (2S + 1) exp

  • 2
  • a(U, S)U
  • ,

(2) where U = E∗ − Erot (S) − δP is thermal excitation energy calculated by taking into account pairing corrections to the empirical mass formula (δP) and rotational energy Erot (S). Level density parameter a(U, S) was calculated as: a(U, S) = ˜ a(U)

  • 1 − h(U/η + S/Sη)

δW U

  • ,

(3) where δW is the shell correction to the liquid-drop mass and ˜ a is smoothed level-density parameter, the function specifying the rate of fadeout is h(x) = tanh x, the fadeout parameter η was set to 18.52 MeV and the parameter Sη was set to 50 . The smoothed level density parametrization depends on the excitation energy of nucleus as: ˜ a(U) = A k∞ − (k∞ − k0) exp

  • −

κ k∞−k0 U A

, (4) where k0 = 7.3, k∞ = 12 and κ = 0.00517 exp(0.0345A). MARIOLA K-G (KRAKÓW) COMEX5 KRAKÓW, 14-18.09.2015 23 / 23