EPS-HEP 2015 DOUBLE-SCATTERING MECHANISM. Antoni Szczurek 1,2 Mariola Kłusek-Gawenda 1

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Mariola Kłusek-Gawenda Institute of Nuclear Physics PN Kraków

1 EPS-HEP 5 DOUBLE-SCTTERING MECHNISM OF PRODUCTION OF TWO MESONS IN ULTRPERIPHERL, ULTRRELTIISTIC HEY ION COLLISIONS ntoni Szczurek, Mariola Kłusek-Gawenda Institute of Nuclear Physics PN Kraków University of Rzeszów. SZCZUREK (INP PS KRKÓW) EPS-HEP 5 WIEN, -9 JULY 5 / 5

2 INTRODUCTION MESONS PRODUCTION γγ fusion Equivalent photon approximation γγ low-energy bump DM-Regge form factor nuclear photoproduction production mass smearing STR & LICE data 3 production + +. SZCZUREK (INP PS KRKÓW) EPS-HEP 5 4 ConclusionsWIEN, -9 JULY 5 / 5

3 EP EQUILENT PHOTON PPROXIMTION b R The strong electromagnetic field is a source of photons that induce electromagnetic reactions in ion-ion collisions. R ULTRPERIHERL COLLISIONS b > R min = R + R. SZCZUREK (INP PS KRKÓW) EPS-HEP 5 WIEN, -9 JULY 5 3 / 5

4 EP - γγ FUSION NUCLER CROSS SECTION n(ω ) X σ γγ X b n(ω ) σ X = X φ b b n(ω) = R min bdb N(ω, b) dω dω n(ω )n(ω )σ γγ X (ω,ω ) =... = N (ω, b ) N (ω, b )Sabs (b) ( ) σ γγ X s bdb db x db y W γγ dw γγ dy X. SZCZUREK (INP PS KRKÓW) EPS-HEP 5 WIEN, -9 JULY 5 4 / 5

5 EP - γγ FUSION ELEMENTRY CROSS SECTION ρ ) [nb] σ(γγ ρ σ low energy γγ `Wγγ Low energy High energy TSSO CELLO TPC /Two γ PLUTO RGUS L W γγ [Ge] σ high energy ˆtmax (ŝ) γγ = R dσ high energy γγ dˆt dˆt ˆt min (ŝ) dσ high energy γγ dˆt = Mγγ ρ 6ŝ ŝ,ˆt; q, q z } { C γ C γ M ŝ,ˆt; q, q B IP ŝ,ˆt C IP s ŝ F ˆt; q F ˆt; q γ(q ) γ(q ) {z }! αip ˆt! αir ˆt ŝ + η IR ŝ,ˆt C IR s ŝ ˆt C Reference: M. Kłusek, W. Schäfer and. Szczurek Exclusive production of pairs in γγ collisions at RHIC, Phys.Lett. B674 (9) 9. SZCZUREK (INP PS KRKÓW) EPS-HEP 5 WIEN, -9 JULY 5 5 / 5

6 EP - γγ FUSION - FORM FCTOR N ( ω /, b / ) depends on the form factor realistic monopole ρ )/db [nb/fm] dσ(uu uuρ s NN = Ge F realistic, F monopole γγ, Low energy γγ, DM Regge ρ )/db [nb/fm] dσ(pbpb PbPbρ s NN = 5.5 Te F realistic, F monopole γγ, Low energy γγ, DM Regge b [fm] b [fm]. SZCZUREK (INP PS KRKÓW) EPS-HEP 5 WIEN, -9 JULY 5 6 / 5

7 ECTOR MESON PHOTOPRODUCTION +. SZCZUREK (INP PS KRKÓW) EPS-HEP 5 WIEN, -9 JULY 5 7 / 5

8 ECTOR MESON PHOTOPRODUCTION γn N + N N N = n, p Parameters fixed to describe HER data: we expect: dσ(γn ρ n) dt dσ(γp ρ n) dt. SZCZUREK (INP PS KRKÓW) EPS-HEP 5 WIEN, -9 JULY 5 8 / 5

9 ECTOR MESON PHOTOPRODUCTION SINGLE MESON PRODUCTION dσ d bdy = dp γip (b, y) dy + dp IPγ (b, y) dy P / (b, y) = ω / Ñ ( ω /, b ) σ γ/ / (W γ/ ) σ γ = dσ γ (t = ) dt t max dt F (t) nuclear form factor. SZCZUREK (INP PS KRKÓW) EPS-HEP 5 WIEN, -9 JULY 5 9 / 5

10 ECTOR MESON PHOTOPRODUCTION SEMI-CLSSICL MODEL FOR γ RECTION σ γ = dσ γ (t=) dt σ tot t max dt F (t) dσ γ (t=) dt = αemσ tot( ) 4f quasi-glauber (classical Glauber): ( σ tot ) = ( ( d ( r exp σ tot p ) )) T (r) quantum mechanical Glauber: ( ) = ( d r exp σ qm tot ( p ) = 6 dσ p p (t=) ( σ tot ( p ) T (r) )) nucleus thickness: T (r) = R dzρ q r + z «dt dσ p p (t=) dt = f dσ γp p (t=) 4α em dt (DM) dσ γp p (t=) dt = B (XW ǫ + YW η ) HER data. SZCZUREK (INP PS KRKÓW) EPS-HEP 5 WIEN, -9 JULY 5 / 5

11 ECTOR MESON PHOTOPRODUCTION S GLUBER MODEL )/dy [mb] dσ(uu uuρ STR Glauber quantum mech. Glauber classical mech y [mb )/dy dσ(pbpb PbPbρ LICE Glauber quantum mech. Glauber classical mech y 4 6. SZCZUREK (INP PS KRKÓW) EPS-HEP 5 WIEN, -9 JULY 5 / 5

12 ECTOR MESON PHOTOPRODUCTION SMERING OF MSS dσ ρ dm dy = f(m) dσ (y, m) dy f(m) = (m) N orm (m) N orm dm N orm (m) dm = mm Γ (m) (m) = BW m m + im Γ (m) + B m running width: Γ (m) = Γ m ( m 4m m 4m ρ ) 3/. SZCZUREK (INP PS KRKÓW) EPS-HEP 5 WIEN, -9 JULY 5 / 5

13 ECTOR MESON PHOTOPRODUCTION SMERING OF MSS mm Γ (m) (m) = BW m m + im Γ (m) + B m Γ (m) = Γ m ( m 4m m 4m ρ ) 3/ Parameter ZEUS STR LICE m [Ge].77 ±..775 ±.3.76 ±.3 Γ [Ge].46 ±.3.6 ±.7.5 ± 5.5 B BW [Ge / ] ±.8.5 ±.4 m [Ge] (.55.) (.5.) (.8.5). SZCZUREK (INP PS KRKÓW) EPS-HEP 5 WIEN, -9 JULY 5 3 / 5

14 ECTOR MESON PHOTOPRODUCTION SMERING OF MSS N orm (m) ZEUS mm Γ (m) STR (m) = BW m m + im Γ (m) + B LICE - m Γ (m) = Γ m B W ) B W cont. 3/ ( m 4m m 4m ρ Parameter ZEUS STR LICE m [Ge].77 ±..775 ±.3.76 ±.3 Γ [Ge].46 ±.3.6 ±.7.5 ± 5.5 B BW [Ge / - ] ±.8.5 ± m [Ge] (.55.) m [Ge] (.5.) (.8.5). SZCZUREK (INP PS KRKÓW) EPS-HEP 5 WIEN, -9 JULY 5 4 / 5

15 ECTOR MESON PHOTOPRODUCTION SINGLE MESON PRODUCTION [mb] )/dy dσ(uu uuρ STR GM FSZ Our results m const KN m =const y [mb] )/dy dσ(pbpb PbPbρ LICE Our results 5 m const m =const y. SZCZUREK (INP PS KRKÓW) EPS-HEP 5 WIEN, -9 JULY 5 5 / 5

16 ECTOR MESON PHOTOPRODUCTION SINGLE MESON PRODUCTION GM FSZ KN Our result Experimental data m = const m const snn = 3 Ge; full y STR ± 7 ± 8 snn = 3 Ge; y < STR ± 5 ± 4 snn = Ge; full y STR ± 8 ± 55 snn =.76 Te; full y LICE ± +5 snn =.76 Te; y <.5 LICE ± +4 5 GM -.P. Gonçalves and M..T. Machado, The QCD pomeron in ultraperipheral heavy ion collisions. I. Photonuclear production of vector mesons, Eur. Phys. J. C4 (5) 59, FSZ - L. Frankfurt, M. Strikman and M. Zhalov, Signals for black body limit in coherent ultraperipheral heavy ion collisions Phys. Lett. B537 () 5, KN - S. Klein and J. Nystrand, Exclusive vector meson production in relativistic heavy ion collisions, Phys. Rev. C6 (999) 493. SZCZUREK (INP PS KRKÓW) EPS-HEP 5 WIEN, -9 JULY 5 6 / 5

17 ECTOR MESON PHOTOPRODUCTION DOUBLE-SCTTERING MECHNISM dσ = ( dpγip (b, y ) + dp ) IPγ (b, y ) dy dy dy dy ( dpγip (b, y ). + dp ) IPγ (b, y ) d b dy dy ( s have negligibly small transverse momenta). SZCZUREK (INP PS KRKÓW) EPS-HEP 5 WIEN, -9 JULY 5 7 / 5

18 ECTOR MESON PHOTOPRODUCTION DOUBLE-SCTTERING MECHNISM S γγ FUSION [mb] s NN = Ge Double scattering γγ, Low energy γγ, DM Regge [mb] s NN = 5.5 Te )/dy dσ(uu uuρ ρ )/dy dσ(pbpb PbPbρ ρ y y. SZCZUREK (INP PS KRKÓW) EPS-HEP 5 WIEN, -9 JULY 5 8 / 5

19 ECTOR MESON PHOTOPRODUCTION DOUBLE-SCTTERING MECHNISM IPγ-IPγ γip-ipγ (mb) - - (mb) - - dy -3 dy -3 dσ/dy -5 dσ/dy y y -6 4 y y γip-γip IPγ-γIP (mb) dy (mb) dy dσ/dy -5 dσ/dy y y -6 4 y y. SZCZUREK (INP PS KRKÓW) EPS-HEP 5 WIEN, -9 JULY 5 9 / 5

20 - - ECTOR MESON PHOTOPRODUCTION - - DOUBLE-SCTTERING MECHNISM T RHIC η < [mb/ge] )/dp + + dσ(uu uu Double scattering γγ, Low energy γγ, DM Regge p [Ge] [mb/ge] 4 )/dm + + dσ(uu uu STR s NN = Ge Fit Double scattering γγ, Low energy γγ, DM Regge M 4 [Ge] missing mechanisms: (45) 4 (7) 4?. SZCZUREK (INP PS KRKÓW) EPS-HEP 5 WIEN, -9 JULY 5 / 5

21 ECTOR MESON PHOTOPRODUCTION DOUBLE-SCTTERING MECHNISM T LHC )/db [mb/fm] dσ(pbpb PbPbρ s NN =.76 Te [mb] )/dη dσ(pbpb PbPb s NN =.76 Te η full η <.5 η <. [mb/ge] )/dp dσ(pbpb PbPb b [fm] η full - s NN =.76 Te η <.5 η < p [Ge] [mb/ge] - 4 )/dm dσ(pbpb PbPb η s NN =.76 Te η full η <.5 η < M 4 [Ge]. SZCZUREK (INP PS KRKÓW) EPS-HEP 5 WIEN, -9 JULY 5 / 5

22 ECTOR MESON PHOTOPRODUCTION COMPRISON OF THE MECHNISMS Energy mechanism σ tot [mb] RHIC ( s NN = Ge) double-scattering.6 in γγ fusion. + + in γγ fusion. Reference: M. Kłusek-Gawenda and. Szczurek Double-scattering mechanism in the exclusive reaction in ultrarelativistic collisions, Phys. Rev. C89 (4) 49. SZCZUREK (INP PS KRKÓW) EPS-HEP 5 WIEN, -9 JULY 5 / 5

23 ECTOR MESON PHOTOPRODUCTION - TWO-PION PRODUCTION 5 4 s NN = 3.5 Te γip (77) γip (45) γγ + [mb/ge] dσ/dm [Ge] M + - Reference: M. Kłusek-Gawenda and. Szczurek, + and pair production in photon-photon and in ultraperipheral ultrarelativistic heavy ion collisions, Phys. Rev. C87 (3) SZCZUREK (INP PS KRKÓW) EPS-HEP 5 WIEN, -9 JULY 5 3 / 5

24 ECTOR MESON PHOTOPRODUCTION - TWO-PION PRODUCTION Impact parameter space approach Smearing of meson Good description of STR and LICE data for single- (77) production Drell-Söding+f (7) colored solid lines - Γ = 5. Me colored dashed lines - Γ = 4 Me LICE data arxiv: ( Y + - <.5) [b/ge] dσ / dm Soding(res+cont) - from γγ + Pb-Pb; s NN =.76 Te M - [Ge] +. SZCZUREK (INP PS KRKÓW) EPS-HEP 5 WIEN, -9 JULY 5 4 / 5

25 ECTOR MESON PHOTOPRODUCTION CONCLUSIONS Comparison of four-pion production via production γγ fusion nuclear double-photoproduction (very large) with STR data Missing contributions (?) (45) (7) Multiple Coulomb excitations associated with production may cause additional excitation of one or both nuclei to the giant resonance region (can be calculated) Reference: M. Kłusek-Gawenda, M. Ciemała, W. Schäfer and. Szczurek Electromagnetic excitation of nuclei and neutron evaporation in ultrarelativistic ultraperipheral heavy ion collisions Phys. Rev. C89 (4) 5497 Thank You. SZCZUREK (INP PS KRKÓW) EPS-HEP 5 WIEN, -9 JULY 5 5 / 5

26 ECTOR MESON PHOTOPRODUCTION CONCLUSIONS Comparison of four-pion production via production γγ fusion nuclear double-photoproduction (very large) with STR data Missing contributions (?) (45) (7) Multiple Coulomb excitations associated with production may cause additional excitation of one or both nuclei to the giant resonance region (can be calculated) Reference: M. Kłusek-Gawenda, M. Ciemała, W. Schäfer and. Szczurek Electromagnetic excitation of nuclei and neutron evaporation in ultrarelativistic ultraperipheral heavy ion collisions Phys. Rev. C89 (4) 5497 Thank You. SZCZUREK (INP PS KRKÓW) EPS-HEP 5 WIEN, -9 JULY 5 5 / 5

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