Semiexclusive production of vector mesons in proton-proton - PowerPoint PPT Presentation

ANNA CISEK Semiexclusive production of vector mesons in proton-proton collisions with electromagnetic dissociation of protons Anna Cisek University of Rzeszow MESON 2018 - 15 th International Workshop on Meson Physics Kraków, 7-12 June 2018 MESON2018 Semiexclusive production of vector mesons 1 / 18

ANNA CISEK Outline Introduction 1 Exclusive production of vector meson Diffractive resonance with strong disociation Diffractive partonic with strong disociation Diffractive production with electromagnetic dissociation Semiexclusive production with electromagnetic dissociation 2 Formalism Results Anna Cisek, Wolfgang Schäfer, Antoni Szczurek MESON2018 Semiexclusive production of vector mesons 2 / 18

Introduction ANNA CISEK Introduction Exclusive production of heavy vector mesons in proton-proton collisions has been studied in rapidyty range y ∼ 2 . 0 − 4 . 5 Large rapidity gaps: no exchange of charge or color. t -channel exchanges with the Regge intercept α ( 0 ) or spin J ≥ 1. We often have to deal with diffractive reactions which include excitation of incoming protons. Instead of fully inclusive final states: gap cross sections, or even only vetos on additional tracks(!) from a production vertex. Inelastic state of mass M X populates a rapidity interval ∆ y ∼ log( M 2 X / m 2 p ) . A background for exclusive production – or a possible signal when looking for large p T vector mesons with a gap. MESON2018 Semiexclusive production of vector mesons 3 / 18

Introduction ANNA CISEK Diagram for exclusive production of vector meson in proton-proton collisions t Pom t Pom t ′ t ′ 1 p 1 t 1 p 1 t p p p p k 1 γ k 1 p vt J/ Ψ S el S el p vt k 2 J/ Ψ k 2 γ p 2 t p 2 t p p p p t ′ t ′ 2 2 Pomeron-photon photon-Pomeron MESON2018 Semiexclusive production of vector mesons 4 / 18

Introduction ANNA CISEK Difractive resonance with strong disociation p p p R γ P J/ Ψ J/ Ψ γ P R p p p low p T → Dissociation into nucleon resonances/low mass continuum + , N ∗ ( 2220 ) , J P = 9 + , states. Dominated by N ∗ ( 1680 ) , J P = 5 2 2 N ∗ ( 2700 ) , J P = 13 + . 2 A model by L.L. Jenkovszky, O.E. Kuprash, J.W. Lämsa, V.K. Magas and R. Orava (2011). large p T → Incoherent diffractive photoproduction of J /ψ off partons. Large diffractive masses are possible here. MESON2018 Semiexclusive production of vector mesons 5 / 18

Introduction ANNA CISEK Difractive partonic with strong disociation p R 1 p p γ M x 1 J/ Ψ W ˆ t P W ˆ P t J/ Ψ M x 2 γ p p R 2 p dissociative production of vector mesons at large p T probes the perturbative QCD Pomeron. (Ryskin, Forshaw et al.). An alternative to the “jet - gap - jet” type of processes. MESON2018 Semiexclusive production of vector mesons 6 / 18

Introduction ANNA CISEK Diagrams representation of the electromagnetic excitation p p X 1 p J/ Ψ γ J/ Ψ γ p X 2 p p The schematic diagrams representation of the electromagnetic excitation of one (left panel) or second (right panel) photon Anna Cisek, Wolfgang Schäfer, Antoni Szczurek Phys. Let. B769 (2017) 176 MESON2018 Semiexclusive production of vector mesons 7 / 18

Semiexclusive production with electromagnetic dissociation ANNA CISEK Diffractive production with electromagnetic dissociation The importent property of these processes is that the p γ ⋆ → X transition is given by the electromagnetic structure function of protons The cross section for such proces can be written as: � d 2 q d σ γ ∗ p → Vp d σ ( pp → XVp ; s ) γ/ p ( z + , q 2 ) 1 π q 2 F ( in ) ( z + s , t = − ( q − p ) 2 ) = dyd 2 p π dt +( z + ↔ z − ) V / √ s � p 2 + m 2 z ± = e ± y Generalization of the Weizsäcker-Williams flux to dissociative processes. Must in principle add contributions of longitudinal photons. Negligible for heavy mesons as long as Q 2 ≪ m 2 V MESON2018 Semiexclusive production of vector mesons 8 / 18

Semiexclusive production with electromagnetic dissociation ANNA CISEK Diffractive production with electromagnetic dissociation The flux of photons associated with the breakup of protons is calculable in terms of the structure function of protons F 2 ( x Bj , Q 2 ) X ) = α em F ( inel ) γ/ p ( z , q 2 , M 2 π ( 1 − z ) θ ( M 2 X − M 2 thr ) · X + Q 2 − m 2 M 2 p q 2 � 2 � · q 2 + z ( M 2 X − m 2 p ) + z 2 m 2 p where 1 Q 2 = � q 2 + z ( M 2 � X − m 2 p ) + z 2 m 2 p 1 − z Q 2 x Bj = Q 2 + M 2 X − m 2 p MESON2018 Semiexclusive production of vector mesons 9 / 18

Semiexclusive production with electromagnetic dissociation ANNA CISEK Structure function of protons Useful fits to F2 H. Abramowicz, E. M. Levin, A. Levy and U. Maor Phys. Lett. B269 , (1991) 465 Q 2 F 2 ( x , Q 2 ) = F P 2 ( x , Q 2 ) + F R 2 ( x , Q 2 ) � � Q 2 + m 2 0 Useful fits to F2 R. Fiore, A. Flachi, L. L. Jenkovszky, A. I. Lengyel and V. K. Magas - Phys. Rev. D70 , 054003 (2004) � R e α ( s n ) � s − s n I m α ( s ) = s δ � · θ ( s − s n ) c n s � ∞ n ds ′ I m α ( s ′ ) R e α ( s ) = α ( 0 ) + s π PV s ′ ( s ′ − s ) 0 MESON2018 Semiexclusive production of vector mesons 10 / 18

Semiexclusive production with electromagnetic dissociation ANNA CISEK Structure function of protons Useful fits to F2 A. Szczurek, V. Uleshchenko Eur. Phys. J. C12 (200) 663-671 2 ( x , Q 2 ) = F N , VDM ( x , Q 2 ) + F N , part F N ( x , Q 2 ) 2 2 VN ( s 1 / 2 ) ( x , Q 2 ) = Q 2 M 4 V · σ tot F N , VDM � V ) 2 · Ω V ( x , Q 2 ) V ( Q 2 + M 2 2 γ 2 π V Q 2 F N , part ( x , Q 2 ) = · F asymp x , ¯ Q 2 ) (¯ Q 2 + Q 2 2 2 0 MESON2018 Semiexclusive production of vector mesons 11 / 18

Semiexclusive production with electromagnetic dissociation ANNA CISEK Rapidity distribution- different structure function of proton s = 7 TeV ALLM s = 7 TeV ALLM s = 7 TeV ALLM VDM VDM VDM M = 10 GeV M = 10 GeV M = 10 GeV X,max X,max X,max Fiore Fiore Fiore − 1 10 SU SU SU )/dy (nb) 10 )/dy (pb) 10 b) µ )/dy ( − 2 10 Ψ Υ φ (J/ ( 1 ( 1 σ σ d σ d 10 − 3 d − 4 − 1 − 1 10 10 10 − 6 − 4 − 2 0 2 4 6 − 6 − 4 − 2 0 2 4 6 − 6 − 4 − 2 0 2 4 6 y y y s = 13 TeV ALLM s = 13 TeV ALLM s = 13 TeV ALLM VDM VDM VDM M = 10 GeV M = 10 GeV M = 10 GeV X,max X,max X,max Fiore Fiore Fiore 10 − 1 SU SU SU )/dy (nb) 10 )/dy (pb) b) 10 µ )/dy ( − 2 10 Ψ φ Υ (J/ ( 1 ( σ σ 1 d σ d − 3 10 d 10 − 4 10 − 1 10 − 1 − 6 − 4 − 2 0 2 4 6 − 6 − 4 − 2 0 2 4 6 − 6 − 4 − 2 0 2 4 6 y y y preliminary results MESON2018 Semiexclusive production of vector mesons 12 / 18

Semiexclusive production with electromagnetic dissociation ANNA CISEK Transverse momentum distribution- different structure function of proton 1 10 2 10 2 s = 7 TeV s = 7 TeV s = 7 TeV 10 − 1 M = 10 GeV (nb/GeV) M = 10 GeV M = 10 GeV X,max X,max X,max (pb/GeV) b/GeV) 10 10 − 2 10 1 1 − 3 µ 10 ( t )/dp t t )/dp )/dp 4 10 − − 1 1 10 10 − Ψ φ Υ − 5 (J/ 10 ( ( σ σ d ALLM σ 10 − 2 ALLM 10 − 2 ALLM d d 10 − 6 Fiore Fiore Fiore VDM VDM VDM SU SU SU − 7 − 3 − 3 10 10 10 0 1 2 3 4 5 0 1 2 3 4 5 0 1 2 3 4 5 p (GeV) p (GeV) p (GeV) 2 2 1 10 10 t t t s = 13 TeV s = 13 TeV s = 13 TeV 1 M = 10 GeV (nb/GeV) M = 10 GeV M = 10 GeV 10 − X,max X,max X,max (pb/GeV) b/GeV) 10 10 10 − 2 1 1 10 − 3 µ ( t )/dp t t )/dp )/dp − 4 10 − 1 − 1 10 10 Ψ Υ φ − 5 (J/ ( 10 ( σ σ 2 2 d ALLM σ 10 − ALLM d 10 − ALLM 6 Fiore d Fiore Fiore 10 − VDM VDM VDM SU SU SU 10 − 7 10 − 3 10 − 3 0 1 2 3 4 5 0 1 2 3 4 5 0 1 2 3 4 5 p (GeV) p (GeV) p (GeV) t t t preliminary results MESON2018 Semiexclusive production of vector mesons 13 / 18

Semiexclusive production with electromagnetic dissociation ANNA CISEK Rapidity distribution - meson comparison 10 3 10 3 10 3 s = 7 TeV φ s = 7 TeV φ s = 7 TeV φ J/ J/ J/ 10 2 M = 10 GeV Ψ 10 2 M = 10 GeV Ψ 10 2 M = 10 GeV Ψ X,max X,max X,max Υ Υ Υ ALLM Fiore SU 10 10 10 /dy (nb) /dy (nb) /dy (nb) 1 1 1 1 1 1 10 − 10 − 10 − σ σ σ d d d 10 − 2 10 − 2 10 − 2 10 − 3 10 − 3 10 − 3 − 4 − 4 − 4 10 10 10 − 6 − 4 − 2 0 2 4 6 − 6 − 4 − 2 0 2 4 6 − 6 − 4 − 2 0 2 4 6 y y y 3 3 3 10 10 10 φ s = 13 TeV φ φ s = 13 TeV s = 13 TeV M = 10 GeV J/ Ψ 2 M = 10 GeV J/ Ψ 2 X,max 2 M = 10 GeV J/ Ψ 10 10 10 X,max Fiore X,max Υ ALLM Υ SU Υ 10 10 10 /dy (nb) /dy (nb) /dy (nb) 1 1 1 10 − 1 10 − 1 10 − 1 σ σ σ d d d − 2 − 2 − 2 10 10 10 − 3 − 3 − 3 10 10 10 4 4 4 10 − 10 − 10 − − 6 − 4 − 2 0 2 4 6 − 6 − 4 − 2 0 2 4 6 − 6 − 4 − 2 0 2 4 6 y y y preliminary results MESON2018 Semiexclusive production of vector mesons 14 / 18