New Results On Energy and Momentum Conservation in Meson Production for A+A Collisions at SPS Energies A. Rybicki, A. Szczurek, M. Kiełbowicz, K. Mazurek, V. Ozvenchuk H. Niewodniczański Institute of Nuclear Physics Polish Academy of Sciences 1) Prologue ; 2) EM fields ; 3) Fire streaks ; 4) Summary. 1 A. Rybicki et al., MESON 2018, 7-12 Jun 2018, Kraków, PL
by I. Sputowska 1) Prologue 2 A. Rybicki et al., MESON 2018, 7-12 Jun 2018, Kraków, PL
spectator Nucleus-nucleus I. Sputowska system collisions: _ √ s NN = 17 GeV participant zone produced particles ( π mesons) by I. Sputowska ● Charged spectators generate electromagnetic fields. ● These modify charged pion spectra in the final state. ● We use this effect as a new source of information on the space-time evolution of the system. ● This brings us to a specific energy-momentum conservation picture in the initial stage. 3 A. Rybicki et al., MESON 2018, 7-12 Jun 2018, Kraków, PL
spectator Nucleus-nucleus I. Sputowska system collisions: _ √ s NN = 17 GeV participant zone produced particles ( π mesons) by I. Sputowska ● Charged spectators generate electromagnetic fields. ● New exp. data from NA61/SHINE@SPS. ● These modify charged pion spectra in the final state. ● New info on the ● We use this effect as a new source of information on space-time evolution the space-time evolution of the system. of both participants and spectators . ● New, specific “ energy-momentum conservation picture ” of the initial stage of the collision. ● 4 A. Rybicki et al., MESON 2018, 7-12 Jun 2018, Kraków, PL
2) electromagnetic fields 5 A. Rybicki et al., MESON 2018, 7-12 Jun 2018, Kraków, PL
A. Rybicki, Acta. Phys. NA49 preliminary NA61/SHINE preliminary NA61/SHINE preliminary Polon. B42 (2011) 867 Ar+Sc @ 150 A GeV/ c Ar+Sc @ 150 A GeV/ c Pb+Pb @ 158 A GeV/ c 1.2 peripheral intermediate central <N w > = 54 ± 11 (a) 1 0.8 0.6 0.4 0.2 <N w > = 69.0 ± 2.1 <N w > = 47.2 ± 2.3 0 -0.1 0 0.1 0.2 0.3 0.4 0.5 0 0.1 0.2 0.3 0.4 0.5 0 0.1 0.2 0.3 0.4 0.5 x F x F x F p L A. Marcinek, spectator velocity: x F = (c.m.s.) MESON 2018, beam p L y = y beam this session. (a) Peripheral Pb+Pb ( Q SPECTATOR ≈ 70 e.u.) Charged → large EM effect, π + /π - ≈ 0. spectators (EM field) (b) Intermediate Ar+Sc ( Q SPECTATOR ≈ 8 e.u) → visible EM effect, breaks isospin symmetry. (c) Central Ar+Sc ( Q SPECTATOR ≈ 3 e.u.) Repulsion ( for π + ) → still visible shadow of EM effect. Attraction ( for π − ) 6 A. Rybicki et al., MESON 2018, 7-12 Jun 2018, Kraków, PL
Ar+Sc data compared to MC simulation Plot from: M. Kiełbowicz, WPCF 2018 Ar+Sc @ 150 A GeV/ c NA61/SHINE p T =25 MeV/c NA61/SHINE preliminary Intermediate preliminary Ar+Sc @ 150 A GeV/ c new information on the space-time evolution Intermediate π + /π − of π production in Ar+Sc collisions →d E . stable spectator cannot describe the data: significant expansion velocity → β . β π + /π − radial expansion d E space-time π + /π − evolution Pl d E ot by p L V. O x F = <N w > = 47.2±2.3 zv beam p L en y ≈ y beam ch 9/14 uk x F spectator velocity of particle production (!) 7 A. Rybicki et al., MESON 2018, 7-12 Jun 2018, Kraków, PL
Ar+Sc data compared to MC simulation Plot from: M. Kiełbowicz, WPCF 2018 Ar+Sc @ 150 A GeV/ c NA61/SHINE p T =25 MeV/c NA61/SHINE preliminary Intermediate preliminary Ar+Sc @ 150 A GeV/ c new information on the space-time evolution Intermediate π + /π − of π production in Ar+Sc collisions →d E . stable spectator cannot describe the data: significant expansion velocity → β . β π + /π − radial expansion d E space-time π + /π − evolution Pl d E ot by p L V. O x F = <N w > = 47.2±2.3 zv beam p L en y ≈ y beam ch uk x F spectator velocity of particle production (!) 8 A. Rybicki et al., MESON 2018, 7-12 Jun 2018, Kraków, PL
Ar+Sc data compared to MC simulation Plot from: M. Kiełbowicz, WPCF 2018 Ar+Sc @ 150 A GeV/ c NA61/SHINE p T =25 MeV/c NA61/SHINE preliminary Intermediate preliminary Ar+Sc @ 150 A GeV/ c new information on the space-time evolution Intermediate π + /π − of π production in Ar+Sc collisions →d E . stable spectator cannot describe the data: significant expansion velocity → β . β π + /π − radial expansion d E space-time π + /π − evolution Pl d E ot by p L V. O x F = <N w > = 47.2±2.3 zv beam p L en y ≈ y beam ch 9/14 uk x F spectator velocity of particle production (!) 9 A. Rybicki et al., MESON 2018, 7-12 Jun 2018, Kraków, PL
Ar+Sc data compared to MC simulation Plot from: M. Kiełbowicz, WPCF 2018 Ar+Sc @ 150 A GeV/ c NA61/SHINE p T =25 MeV/c NA61/SHINE preliminary Intermediate preliminary Ar+Sc @ 150 A GeV/ c new information on the space-time evolution Intermediate π + /π − of π production in Ar+Sc collisions →d E . stable spectator cannot describe the data: significant expansion velocity → β . β d E =0.5 fm, β=0.3 π + /π − radial expansion d E space-time π + /π − evolution Pl d E ot by p L V. O x F = <N w > = 47.2±2.3 zv beam p L en y ≈ y beam ch 9/14 uk x F spectator velocity of particle production (!) 10 A. Rybicki et al., MESON 2018, 7-12 Jun 2018, Kraków, PL
Ar+Sc data compared to MC simulation Plot from: M. Kiełbowicz, WPCF 2018 Ar+Sc @ 150 A GeV/ c NA61/SHINE p T =25 MeV/c STAR NA49 WA98 NA61/SHINE preliminary Intermediate preliminary Ar+Sc @ 150 A GeV/ c A.R. et al., APP Supp. 9 (2016) 303 and references therein ( π + /π − ) (v 1 ) (v 1 ) Intermediate π + /π − Au+Au, Pb+Pb 7.7-17.3 GeV preliminary preliminary preliminary d E =0.5 fm, β=0.3 π + /π − Ar+Sc radial expansion d E space-time π + /π − evolution Pl d E ot by p L V. O x F = <N w > = 47.2±2.3 zv beam p L en y ≈ y beam ch 9/14 uk x F spectator velocity of particle production (!) 11 A. Rybicki et al., MESON 2018, 7-12 Jun 2018, Kraków, PL
A.R. et al., APP Supp. 9 (2016) 303 and references therein Au+Au, Pb+Pb 7.7-17.3 GeV preliminary preliminary preliminary Ar+Sc radial expansion d E Picture from IFJ PAN press release: google out “fire streaks in collisions” space-time 3) Fire streaks evolution d E d E y ≈ y beam 9/14 of particle production (!) 12 A. Rybicki et al., MESON 2018, 7-12 Jun 2018, Kraków, PL
A. Szczurek., A. R., M. Kiełbowicz, Phys. Rev. C 95 , 024908 (2017) dn/dy dn/dy A.R. et al., APP Supp. 9 (2016) 303 and references therein 1 x 1 fm 2 Au+Au, Pb+Pb 7.7-17.3 GeV b= b= 8.41 fm 6.64 fm y y y local energy-momentum local energy-momentum local energy-momentum R. Hagedorn, CERN-71-12 (1971) dn/dy dn/dy W.D. Myers, Nucl. Phys. A 296 (1978) 177 conservation conservation conservation (Re)invented by A. Szczurek R. Hagedorn, CERN-71-12 (1971) R. Hagedorn, CERN-71-12 (1971) preliminary preliminary preliminary b= b= 4.74 fm 2.55 fm y y Ar+Sc with rapidity from E-p conservation dn/dy radial Pb+Pb expansion π − Peripheral Each fire streak fragments independently into pions Each fire streak fragments independently into pions Central A. Szczurek., A. R., M. Kiełbowicz, Phys. Rev. C 95 , 024908 (2017) y 13 13 Press release: google out “fire streaks in collisions” A. Rybicki et al., MESON 2018, 7-12 Jun 2018, Kraków, PL A. Rybicki et al., MESON 2018, 7-12 Jun 2018, Kraków, PL
_ π − , Pb+Pb, √ s NN = 17.3 GeV A. Szczurek., A. R., M. Kiełbowicz, Phys. Rev. C 95 , 024908 (2017) dn/dy dn/dy dn/dy 1 x 1 fm 2 b= b= b= 9.72 fm 8.41 fm 6.64 fm y y y local energy-momentum local energy-momentum local energy-momentum R. Hagedorn, CERN-71-12 (1971) dn/dy dn/dy W.D. Myers, Nucl. Phys. A 296 (1978) 177 conservation conservation conservation (Re)invented by A. Szczurek R. Hagedorn, CERN-71-12 (1971) R. Hagedorn, CERN-71-12 (1971) b= b= 4.74 fm 2.55 fm y y with rapidity from E-p conservation dn/dy Pb+Pb π − Peripheral Each fire streak fragments independently into pions Each fire streak fragments independently into pions Central A. Szczurek., A. R., M. Kiełbowicz, Phys. Rev. C 95 , 024908 (2017) y 14 Press release: google out “fire streaks in collisions” data points from: NA49 , T. Anticic et al., Phys. Rev. C 86 , 054903 (2012) A. Rybicki et al., MESON 2018, 7-12 Jun 2018, Kraków, PL
_ √ s NN = 17.3 GeV Peripheral (b=9.72 fm) Pb+Pb 1 x 1 fm 2 rapidity Central (b=2.55 fm) local energy-momentum R. Hagedorn, CERN-71-12 W.D. Myers, Nucl. Phys. A conservation (Re)invented by A. Szczurek R. Hagedorn, CERN-71-12 (1971) R. Hagedorn, CERN-71-12 (1971) b [fm] x with rapidity from E-p conservation dn/dy Pb+Pb π − Peripheral Each fire streak fragments independently into pions Central A. Szczurek., A. R., M. Kiełbowicz, Phys. Rev. C 95 , 024908 (2017) y 15 Press release: google out “fire streaks in collisions” data points from: NA49 , T. Anticic et al., Phys. Rev. C 86 , 054903 (2012) A. Rybicki et al., MESON 2018, 7-12 Jun 2018, Kraków, PL
Recommend
More recommend
