Meson production in ultra-peripheral heavy ion collisions C.A. - PowerPoint PPT Presentation

Meson production in ultra-peripheral heavy ion collisions C.A. Bertulani C.A. Bertulani, 8th Workshop of the APS Topical Group on Hadronic Physics, April 11, 2019

Collaboration Fernando Navarra Victor Goncalves Adeola Adeluyi Gerhard Baur Univ. Sao Paulo U Rio Grande do Sul Texas A&M-Commerce KFA-Juelich Michael Murray Mark Ellermann Spencer Klain James Thomas Univ. of Kansas Texas A&M-Commerce Berkeley Lab Texas A&M-Commerce 2 Bertulani


 Pair Production with Capture Bertulani, Baur, Phys. Rep. 163, 299 (1988) σ ∝ Z 8 α 8 ⎡ ⎤ ⎛ ⎞ ln 0.68 γ ⎟− 5 ⎢ ⎥ ⎜ 2 2 3 m e ⎝ ⎠ ⎣ ⎦ ~ 300 b for Pb+Pb at LHC Production of anti-H CERN: Baur et al, 
 PLB 368, 251 (1996) Fermilab: Blanford et al, PRL 80, 3037 (1998) Bertulani, Baur, PRD 58, 034005 (1998) agrees with Fermilab data. 3

1996 Virtual photons, antiatoms, and the public 4

Production of Exotic Atoms Bertulani, Ellermann, PRC 81, 044910 (2010) Probability of muonic atom production in pp 
 collisions at the LHC as a function of the 
 impact parameter. Angular distribution of the positive muon when the negative muon is captured by a proton at the LHC, as a function of the angle that the free muon has with the direction of motion of the muonic atom. 5

Production of Exotic Atoms Bertulani, Ellermann, PRC 81, 044910 (2010) “Exotic” atom pp PbPb Hydrogen 63.4 132 b muonic 44.8 ✕ 10 -4 0.16 mb pionic 21.3 ✕ 10 -4 0.09 mb 1.3 ✕ 10 -4 kaonic 4.3 µb ρ atom 0.51 ✕ 10 -4 1.3 µb protonium 0.09 ✕ 10 -4 0.5 µb Cross sections for production of exotic atoms in pp and PbPb collisions at the CERN Large Hadron Collider (LHC). 6

QFT with Bound states Spin 0,2, C=even Spin 1, C=odd Spin 0 Bodwin, Yennie, Gregorio, Rev. Mod. Phys. 57, 723 (1985) Spin 1 Bertulani, Navarra, NPA703 (2002) 861 Example: parapositronium (S = 0) and orthopositronium (S = 1) 7

QFT with Bound states RECIPE for mesons: • replace electrons by quarks • get rid of | ψ (0)| 2 van Royen, Weisskopf, Nuovo Cim. A 50, 617 (1967) Appelquist, Politzer, PRL 34, 365 (1975) Example: parapositronium (S = 0) at LHC (PbPb) 325 mb σ = Study of positronium propagation in thin metals: 
 QFT for bound states 8

QFT with bound states X ( ω 1 ω 2 s) d ω 1 d ω 2 n γ ( ω 1 ) n γ ( ω 2 ) σ γγ ∫ σ X = ) = 2Z 2 αω 2 ⎡ ⎤ ( ) + 1 2 ξ 2 ξ { } ∞ ∞ ( ( ) d 3 r ρ r ( ) ( ) n ω ,b dbb K 1 γ 2 K 0 exp −σ NN dz' ρ r' − r ∫ ∫ ∫ ⎢ ⎥ πγ 2 0 −∞ ⎣ ⎦ No need for minimum impact ξ = ω b parameter 
 γ c d 3 n ω ,b + rcos φ ( ) dn Baur, Baron, R 2 π d ω = 2 π dbb dr r d φ ∫ ∫ ∫ NPA 561, 628 (1993) d ω d 2 b 0 0 For meson production at CERN use above in conjunction with 
 Low, Phys. Rev. 120, 582 (1960) Γ m X →γγ X (x 1 x 2 s) = 8 π 2 2J + 1 ( ) 2 ( ) δ x 1 x 2 s − m X σ γγ m X 9

Testing widths of various mesons at LHC Bertulani, PRC 79, 047901 (2009) J PC Γ γγ th (keV) Γ γγ exp (keV) Cross section (mb) π 0 (0 -+ ) 3.4 – 6.4 x 10 -3 8.4 ± 0.6 x 10 -3 27 – 52 π (1300) (0 -+ ) 0.43 – 0.49 unknown 0.69 – 0.71 π (1880) 0.74 – 1.0 unknown 0.8 - 1.1 π 2 (1670) (2 -+ ) 0.11 – 0.27 < 0.072 0.41 – 1.1 π 2 (2130) (2 -+ ) 0.10 – 0.16 unknown 0.36 – 0.54 π 2 (2330) 0.21 – 1.6 unknown 0.04 – 0.31 Needs a dedicated experimental collaboration 10

Testing widths of various mesons at LHC Bertulani, PRC 79, 047901 (2009) 11

Testing widths of various mesons at CERN

Parton Distribution Functions (PDFs) W γ p ~ 200 GeV W γ p ~ 1 TeV § HERA: LHC: Gonçalves, Bertulani, PRC 65, 054905 (2002) For heavy quarks the d σ γ g → qq photoproduction can s ( ) σ γ g → qq (s) = dM qq G N x, M qq ∫ be described using dM qq 2m c perturbative QCD, ⎡ ⎤ ⎛ ⎞ d σ γ g → qq 2 = 4 παα s e c ⎛ ⎞ 1 + ε− 1 ⎟ ln 1 + 1 −ε 2 ε 2 ( ) 1 −ε ⎟− 1 + ε ⎢ ⎥ ⎜ ⎟ ⎜ ⎜ 2 dM qq M qq 1 − 1 −ε ⎢ ⎥ ⎝ ⎠ ⎝ ⎠ ⎣ ⎦ 2 ε = 4m q Glueck, Reya, Phys. Lett. 79, 453 (1978) 2 M qq 13

Parton Distribution Functions (PDFs) d ω ( ) ( ) ⊗ σ γ g → qq ⊗ xG A x,Q 2 ( ) = σ AA → XXqq ω n ω ∫ 2 − 1 γ c = 2 γ lab x = M 2p e − y << 1 Bjorken No medium corrections ( ) = A ⊗ xG N x,Q 2 ( ) xG A x,Q 2 medium corrections ( ) = R G ⊗ xG N x,Q 2 ( ) xG A x,Q 2 14

Uncertainties in PDFs Thomas, Bertulani, Brady, Clark, Godat, Olness. ArXiv:1603.01919 Gluon uncertainty for nPDF 15

Parton Distribution Functions (PDFs) Energy dependence of the photoproduction of heavy quarks for distinct nuclear gluon distributions (A = 208). • EKS = Eskola, Kolhinen, Salgado, EPJ. C9, 61 (1999) • AG = Ayala, Gonçalves, EPJ. C 20, 343 (2001) • GRV = Glück, Reya, Vogt, Z. Phys. C67, 433 (1995) 16

Parton Distribution Functions at LHC Rapidity distribution for the photoproduction of charm quarks in 208 Pb + 208 Pb collisions at the LHC. • EKS = Eskola, Kolhinen, Salgado, EPJ. C9, 61 (1999) • AG = Ayala, Gonçalves, EPJ. C 20, 343 (2001) • GRV = Glück, Reya, Vogt, Z. Phys. C67, 433 (1995) 17

Resolved Photons d ω ( ) ( ) = ( ) ⊗ x γ G γ x γ ,Q 2 σ AA → XXqq ω n ω ∫ X ( ) ⊗ σ gg → qq ⊗ xG A x,Q 2 Glück, Owens, Reya, PRD 17, 2324 (1978) ( ) πα 2 s Q 2 ⎡ ⎛ ⎞ ⎛ ⎞ 1 + ε + ε 2 q ( ⌢ ⎟ ln 1 + 1 −ε s) = ⎢ ⎜ ⎟ σ gg → q ! 3 ⌢ ⎜ X ⎜ ⎟ s 16 1 − 1 −ε ⎢ ⎝ ⎠ ⎝ ⎠ ⎣ ⎤ ⎛ ⎞ − 7 4 + 31 ⎟ 1 −ε 16 ε ⎜ ⎥ ⎝ ⎠ ⎦ 18

Resolving resolved photons Rapidity distribution for the photoproduction of charm quarks in 208 Pb + 208 Pb collisions at LHC with (GRV+RES) and without (GRV) the inclusion of the resolved contribution. 19

J/ ψ production at the LHC color dipole approximation 2 Q 2 ( ) ( ) = π 3 Γ ee M J/ ψ 3 d σ γ A → J / ψ α s 2 ⎡ ⎤ ( ) Stronger 
 xG A x,Q 2 ⎣ ⎦ Q 8 dt 48 α dependence on G A t = 0 ( ) d σ γ A → J / ψ d ω 2 ∞ ( ) = ( ) ( ) σ AA → AAJ / ψ n ω dt F t ∫ ∫ dt t min ω t = 0 m J/ ψ = 3.097 GeV Gluon LHC distribution GRV 6.6 mb EKS 2.5 mb AG 0.9 mb Energy dependence of the elastic photoproduction of J/ ψ for distinct nuclear gluon distributions (A = 208). 20

Nuclear modification of PDFs Adeluyi, Bertulani, PRC84, 024916 (2011) dn ( ) ( ( ) ⊗ σ γ g → qq ⊗ xG A x,Q 2 ) = σ AA → XXqq ∫ d ω ω ( ) = R G ⊗ xG N x,Q 2 ( ) xG A x,Q 2 shadowing x ≤ 0.04, R G < 1 anti-shadowing 0.04 ≤ x ≤ 0.3, R G > 1 EMC effect 0.3 ≤ x ≤ 0.8, R G < 1 Fermi motion x > 0.8, R G > 1 • EPS08 = Eskola, Paukunnen, Salgado, JHEP 07, 102 (2008) • EPS09 = Eskola, Paukunnen, Salgado, JHEP 04, 065 (2009) • MSTW08 = Martin, Stirling, Thorne, Watts, EPJ C 63, 189 (2009) (R G ~ 1) • HKN07 = Hirai, Kumano, Nagai, PRC 76, 065207 (2007) 21

Nuclear modification of PDFs Fermi motion anti-shadowing EMC shadowing • EPS08 = Eskola, Paukunnen, Salgado, JHEP 07, 102 (2008) • EPS09 = Eskola, Paukunnen, Salgado, JHEP 04, 065 (2009) • HKN07 = Hirai, Kumano, Nagai, PRC 76, 065207 (2007) 22

Nuclear modification of PDFs × 1 3.5 × 1 Cross section for photoproduction of J/ ψ ( ϒ ) as a function of energy W γ p . m ϒ = 9.46 GeV m J/ ψ = 3.097 GeV 23

Nuclear modification of PDFs in cc production anti-shadowing shadowing Total rapidity distributions of the photoproduction of cc in Pb-Pb collisions at the LHC. 24

Nuclear modification of PDFs in bb production anti-shadowing shadowing Total rapidity distributions of the photoproduction of bb in Pb-Pb collisions at the LHC. 25

Nuclear modification of PDFs in qq-bar prod. Q 2 = s Q 2 = 4m c 2 Gluon distribution (mb) (mb) MST08 1170 1090 EPS08 890 780 EPS09 1000 910 HKN07 1080 1000 Total cross sections for direct photoproduction of cc in ultraperipheral Pb-Pb collisions at the LHC. Gluon Q 2 = s Q 2 = 4m b 2 distribution (mb) (mb) MST08 6.2 7.0 EPS08 5.8 6.2 EPS09 6.0 6.6 HKN07 6.1 6.7 Total cross sections for direct photoproduction of bb in ultraperipheral Pb-Pb collisions at the LHC. 26

Nuclear modification of PDFs at the LHC Gluon LO Scaled LO distribution (mb) (mb) MST08 260 74 EPS08 36 10 EPS09 101 29 HKN07 173 49 Total cross sections for elastic photoproduction of J/ ψ in ultraperipheral Pb-Pb collisions at the LHC. Gluon Cross section distribution (µb) MST08 189 EPS08 99 EPS09 130 HKN07 146 Total cross sections for elastic photoproduction of ϒ (1s) in ultraperipheral Pb-Pb collisions at the LHC. 27