New Results On Energy and Momentum Conservation in Meson Production - - PowerPoint PPT Presentation

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New Results On Energy and Momentum Conservation in Meson Production - - PowerPoint PPT Presentation

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New Results On Energy and Momentum Conservation in Meson Production for A+A Collisions at SPS Energies A. Rybicki, A. Szczurek, M. Kiebowicz, K. Mazurek, V. Ozvenchuk H. Niewodniczaski Institute of Nuclear Physics Polish Academy of

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  • A. Rybicki et al., MESON 2018, 7-12 Jun 2018, Kraków, PL

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.

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  • A. Rybicki et al., MESON 2018, 7-12 Jun 2018, Kraków, PL

1) Prologue

by I. Sputowska

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  • A. Rybicki et al., MESON 2018, 7-12 Jun 2018, Kraków, PL
  • I. Sputowska

by I. Sputowska

Nucleus-nucleus collisions: √sNN= 17 GeV

_

spectator system

participant zone

produced particles (π mesons)

  • 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.

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  • A. Rybicki et al., MESON 2018, 7-12 Jun 2018, Kraków, PL
  • I. Sputowska

by I. Sputowska

spectator system

participant zone

produced particles (π mesons)

  • 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.

  • New, specific “energy-momentum conservation

picture” of the initial stage of the collision.

  • New exp. data from

NA61/SHINE@SPS.

  • New info on the

space-time evolution

  • f both participants

and spectators.

  • Nucleus-nucleus

collisions: √sNN= 17 GeV

_

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  • A. Rybicki et al., MESON 2018, 7-12 Jun 2018, Kraków, PL

2) electromagnetic fields

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  • A. Rybicki et al., MESON 2018, 7-12 Jun 2018, Kraków, PL

<Nw> = 47.2 ± 2.3 <Nw> = 69.0 ± 2.1

  • A. Rybicki, Acta. Phys.
  • Polon. B42 (2011) 867

Charged

spectators (EM field)

Repulsion ( for π+ ) Attraction ( for π− )

(a)

<Nw> = 54 ± 11

NA61/SHINE preliminary Ar+Sc @ 150A GeV/c central NA49 preliminary Pb+Pb @ 158A GeV/c peripheral NA61/SHINE preliminary Ar+Sc @ 150A GeV/c intermediate

0.1 0.2 0.3 0.4 0.5

  • 0.1

0.1 0.2 0.3 0.4 0.5 0.1 0.2 0.3 0.4 0.5 0.2 0.4 0.6 0.8 1.2 1

xF xF xF

xF = pL pL

beam

(c.m.s.)

(a) Peripheral Pb+Pb (QSPECTATOR≈ 70 e.u.) → large EM effect, π+/π- ≈ 0. (b) Intermediate Ar+Sc (QSPECTATOR≈ 8 e.u) → visible EM effect, breaks isospin symmetry. (c) Central Ar+Sc (QSPECTATOR≈ 3 e.u.) → still visible shadow of EM effect.

  • A. Marcinek,

MESON 2018, this session.

y = ybeam spectator velocity:

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  • A. Rybicki et al., MESON 2018, 7-12 Jun 2018, Kraków, PL

Ar+Sc data compared to MC simulation

NA61/SHINE preliminary Ar+Sc @ 150A GeV/c Intermediate

<Nw> = 47.2±2.3

Pl

  • t

by V. O zv en ch uk

 new information on the space-time evolution

  • f π production in Ar+Sc collisions→dE.

 stable spectator cannot describe the data:

significant expansion velocity→β.

dE

β

radial expansion

9/14

y ≈ ybeam

  • f particle production (!)

dE space-time evolution

pT=25 MeV/c

π+/π− π+/π− π+/π−

xF

Plot from:

  • M. Kiełbowicz,

WPCF 2018

NA61/SHINE preliminary Ar+Sc @ 150A GeV/c Intermediate

xF = pL pL

beam

spectator velocity

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  • A. Rybicki et al., MESON 2018, 7-12 Jun 2018, Kraków, PL

Ar+Sc data compared to MC simulation

NA61/SHINE preliminary Ar+Sc @ 150A GeV/c Intermediate

<Nw> = 47.2±2.3 y ≈ ybeam

  • f particle production (!)

dE space-time evolution

Pl

  • t

by V. O zv en ch uk

 new information on the space-time evolution

  • f π production in Ar+Sc collisions→dE.

 stable spectator cannot describe the data:

significant expansion velocity→β.

dE

β

radial expansion

pT=25 MeV/c

π+/π− π+/π− π+/π−

xF

Plot from:

  • M. Kiełbowicz,

WPCF 2018

NA61/SHINE preliminary Ar+Sc @ 150A GeV/c Intermediate

xF = pL pL

beam

spectator velocity

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9

  • A. Rybicki et al., MESON 2018, 7-12 Jun 2018, Kraków, PL

Ar+Sc data compared to MC simulation

NA61/SHINE preliminary Ar+Sc @ 150A GeV/c Intermediate

<Nw> = 47.2±2.3

Pl

  • t

by V. O zv en ch uk

 new information on the space-time evolution

  • f π production in Ar+Sc collisions→dE.

 stable spectator cannot describe the data:

significant expansion velocity→β.

dE

β

radial expansion

9/14

y ≈ ybeam

  • f particle production (!)

dE space-time evolution

pT=25 MeV/c

π+/π− π+/π− π+/π−

xF

Plot from:

  • M. Kiełbowicz,

WPCF 2018

NA61/SHINE preliminary Ar+Sc @ 150A GeV/c Intermediate

xF = pL pL

beam

spectator velocity

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  • A. Rybicki et al., MESON 2018, 7-12 Jun 2018, Kraków, PL

Ar+Sc data compared to MC simulation

NA61/SHINE preliminary Ar+Sc @ 150A GeV/c Intermediate

<Nw> = 47.2±2.3

Pl

  • t

by V. O zv en ch uk

 new information on the space-time evolution

  • f π production in Ar+Sc collisions→dE.

 stable spectator cannot describe the data:

significant expansion velocity→β.

dE

β

radial expansion

9/14

y ≈ ybeam

  • f particle production (!)

dE space-time evolution

dE=0.5 fm, β=0.3

pT=25 MeV/c

π+/π− π+/π− π+/π−

xF

xF = pL pL

beam

Plot from:

  • M. Kiełbowicz,

WPCF 2018

NA61/SHINE preliminary Ar+Sc @ 150A GeV/c Intermediate

spectator velocity

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  • A. Rybicki et al., MESON 2018, 7-12 Jun 2018, Kraków, PL

NA61/SHINE preliminary Ar+Sc @ 150A GeV/c Intermediate

<Nw> = 47.2±2.3

Pl

  • t

by V. O zv en ch uk

dE

radial expansion

9/14

y ≈ ybeam

  • f particle production (!)

dE space-time evolution

preliminary preliminary preliminary

Ar+Sc

dE=0.5 fm, β=0.3

pT=25 MeV/c

π+/π− π+/π− π+/π−

xF

xF = pL pL

beam

Plot from:

  • M. Kiełbowicz,

WPCF 2018

NA61/SHINE preliminary Ar+Sc @ 150A GeV/c Intermediate

Ar+Sc data compared to MC simulation

spectator velocity

A.R. et al., APP Supp. 9 (2016) 303 and references therein

Au+Au, Pb+Pb 7.7-17.3 GeV

STAR (v1) NA49

(π+/π−)

WA98 (v1)

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dE

radial expansion

9/14

y ≈ ybeam

  • f particle production (!)

dE space-time evolution

preliminary preliminary preliminary

Au+Au, Pb+Pb 7.7-17.3 GeV

Ar+Sc

3) Fire streaks

dE

Picture from IFJ PAN press release: google out “fire streaks in collisions” A.R. et al., APP Supp. 9 (2016) 303 and references therein

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  • A. Rybicki et al., MESON 2018, 7-12 Jun 2018, Kraków, PL

with rapidity from E-p conservation Each fire streak fragments independently into pions

Peripheral

Central

y

Pb+Pb

π−

y y y y y

b= 8.41 fm b= 6.64 fm b= 2.55 fm b= 4.74 fm

local energy-momentum conservation

1 x 1 fm2

  • A. Szczurek., A. R., M. Kiełbowicz, Phys. Rev. C 95, 024908 (2017)

local energy-momentum conservation

  • R. Hagedorn, CERN-71-12 (1971)
  • A. Szczurek., A. R., M. Kiełbowicz, Phys. Rev. C 95, 024908 (2017)

Press release: google out “fire streaks in collisions”

dn/dy

dn/dy dn/dy dn/dy

dn/dy

local energy-momentum conservation

  • R. Hagedorn, CERN-71-12 (1971)
  • R. Hagedorn, CERN-71-12 (1971)

W.D. Myers, Nucl. Phys. A 296 (1978) 177

(Re)invented by A. Szczurek

radial expansion

preliminary preliminary preliminary

Au+Au, Pb+Pb 7.7-17.3 GeV

Ar+Sc Each fire streak fragments independently into pions

  • A. Rybicki et al., MESON 2018, 7-12 Jun 2018, Kraków, PL

A.R. et al., APP Supp. 9 (2016) 303 and references therein

13

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  • A. Rybicki et al., MESON 2018, 7-12 Jun 2018, Kraków, PL

with rapidity from E-p conservation Each fire streak fragments independently into pions

Peripheral

Central

y

Pb+Pb

π−

Each fire streak fragments independently into pions

y y y y y

π−, Pb+Pb, √sNN= 17.3 GeV

_

b= 9.72 fm b= 8.41 fm b= 6.64 fm b= 2.55 fm b= 4.74 fm

local energy-momentum conservation

1 x 1 fm2

  • A. Szczurek., A. R., M. Kiełbowicz, Phys. Rev. C 95, 024908 (2017)

local energy-momentum conservation

  • R. Hagedorn, CERN-71-12 (1971)
  • A. Szczurek., A. R., M. Kiełbowicz, Phys. Rev. C 95, 024908 (2017)

Press release: google out “fire streaks in collisions” data points from: NA49, T. Anticic et al., Phys. Rev. C 86, 054903 (2012)

dn/dy

dn/dy dn/dy dn/dy

dn/dy

local energy-momentum conservation

  • R. Hagedorn, CERN-71-12 (1971)
  • R. Hagedorn, CERN-71-12 (1971)

W.D. Myers, Nucl. Phys. A 296 (1978) 177

(Re)invented by A. Szczurek

dn/dy

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  • A. Rybicki et al., MESON 2018, 7-12 Jun 2018, Kraków, PL

local energy-momentum conservation with rapidity from E-p conservation

b [fm]

x

Each fire streak fragments independently into pions rapidity

Central (b=2.55 fm)

√sNN= 17.3 GeV

_ Pb+Pb Peripheral (b=9.72 fm)

y

dn/dy

1 x 1 fm2

  • R. Hagedorn, CERN-71-12 (1971)
  • R. Hagedorn, CERN-71-12 (1971)
  • R. Hagedorn, CERN-71-12

W.D. Myers, Nucl. Phys. A

(Re)invented by A. Szczurek

Peripheral

Central

Pb+Pb

π−

  • A. Szczurek., A. R., M. Kiełbowicz, Phys. Rev. C 95, 024908 (2017)

Press release: google out “fire streaks in collisions” data points from: NA49, T. Anticic et al., Phys. Rev. C 86, 054903 (2012)

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  • A. Rybicki et al., MESON 2018, 7-12 Jun 2018, Kraków, PL

with rapidity from E-p conservation

b [fm]

x

local energy- momentum conservation Each fire streak fragments independently into pions rapidity

Central (b=2.55 fm)

√sNN= 17.3 GeV

_ Pb+Pb Peripheral (b=9.72 fm)

y

dn/dy

Centrality dependence of pion dn/dy spectrum :

  • nly from E-p conservation !

1 x 1 fm2

  • R. Hagedorn, CERN-71-12

W.D. Myers, Nucl. Phys. A

(Re)invented by A. Szczurek

Peripheral

Central

Pb+Pb

π−

  • A. Szczurek., A. R., M. Kiełbowicz, Phys. Rev. C 95, 024908 (2017)

Press release: google out “fire streaks in collisions” data points from: NA49, T. Anticic et al., Phys. Rev. C 86, 054903 (2012)

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  • A. Rybicki et al., MESON 2018, 7-12 Jun 2018, Kraków, PL

dE

β

radial expansion

y ≈ ybeam

  • f particle production (!)

dE space-time evolution

Remark: excitation energy in the spectator system

pT=25 MeV/c √sNN= 17.3 GeV, Pb+Pb peripheral

_

π+/π−

NA49 preliminary β=0 β=0.1 β=0.2 β=0.3

π+/π−

  • K. Mazurek et al., Phys.Rev. C97 (2018) 024604

ABRABLA LSD

Excitation energy [MeV]

Impact Parameter [fm]

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  • A. Rybicki et al., MESON 2018, 7-12 Jun 2018, Kraków, PL

dE

β

radial expansion

9/14

y ≈ ybeam

  • f particle production (!)

dE space-time evolution

Remark: excitation energy in the spectator system

pT=25 MeV/c √sNN= 17.3 GeV, Pb+Pb peripheral

_

π+/π−

NA49 preliminary β=0 β=0.1 β=0.2 β=0.3

π+/π−

  • K. Mazurek et al., Phys.Rev. C97 (2018) 024604

ABRABLA LSD

β= 0.2 ± 0.05

Excitation energy [MeV]

Impact Parameter [fm]

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  • A. Rybicki et al., MESON 2018, 7-12 Jun 2018, Kraków, PL

dE

β

radial expansion

y ≈ ybeam

  • f particle production (!)

dE space-time evolution

Remark: excitation energy in the spectator system

pT=25 MeV/c √sNN= 17.3 GeV, Pb+Pb peripheral

_

NA49 preliminary β=0 β=0.1 β=0.2 β=0.3

π+/π−

  • K. Mazurek et al., Phys.Rev. C97 (2018) 024604

ABRABLA LSD

β= 0.2 ± 0.05

Excitation energy [MeV]

Impact Parameter [fm]

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  • A. Rybicki et al., MESON 2018, 7-12 Jun 2018, Kraków, PL

dE

β

radial expansion

9/14

y ≈ ybeam

  • f particle production (!)

dE space-time evolution

Remark: excitation energy in the spectator system

EM effects can differentiate between models of the spectator initial stage !

pT=25 MeV/c √sNN= 17.3 GeV, Pb+Pb peripheral

_

NA49 preliminary β=0 β=0.1 β=0.2 β=0.3

π+/π−

β= 0.2 ± 0.05

  • K. Mazurek et al., Phys.Rev. C97 (2018) 024604

ABRABLA LSD

Excitation energy [MeV]

Impact Parameter [fm]

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  • A. Rybicki et al., MESON 2018, 7-12 Jun 2018, Kraków, PL
  • … Spectator-induced EM effects brought us from the final state
  • f the reaction ...
  • … into a picture of the longitudinal evolution of the system at

the initial stage at SPS energies, largely governed by energy-momentum conservation...

  • … BUT they also give us a chance to get insight into the spectator

system's excitation energy. Thank you!

4) Summary

π+ π+

β

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  • A. Rybicki et al., MESON 2018, 7-12 Jun 2018, Kraków, PL

Acknowledgments.

This work was supported by the National Science Centre, Poland (grant no. 2014/14/E/ST2/00018).

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  • A. Rybicki et al., MESON 2018, 7-12 Jun 2018, Kraków, PL

Extra slides

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  • A. Rybicki et al., MESON 2018, 7-12 Jun 2018, Kraków, PL

with rapidity from E-p conservation

b [fm]

x

local energy- momentum conservation Each fire streak fragments independently into pions rapidity

Central (b=2.55 fm)

√sNN= 17.3 GeV

_ Pb+Pb Peripheral (b=9.72 fm)

y

dn/dy Pb+Pb

π−

Centrality dependence of pion dn/dy spectrum :

  • nly from E-p conservation !

1 x 1 fm2

  • R. Hagedorn, CERN-71-12

W.D. Myers, Nucl. Phys. A

(Re)invented by A. Szczurek

Peripheral

Central

Peripheral

Central

  • A. Szczurek., A. R., M. Kiełbowicz, Phys. Rev. C 95, 024908 (2017)

Press release: google out “fire streaks in collisions” data points from: NA49, T. Anticic et al., Phys. Rev. C 86, 054903 (2012)

(Pb+Pb) / (Pb+Pb)peripheral

π−

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  • A. Rybicki et al., MESON 2018, 7-12 Jun 2018, Kraków, PL

with rapidity from E-p conservation

b [fm]

x

rapidity

Central (b=2.55 fm)

√sNN= 17.3 GeV

_ Pb+Pb Peripheral (b=9.72 fm) Peripheral Central

dn/dy Pb+Pb

π−

1 x 1 fm2

Remark (1): excitation energy in the participant zone...

E*

s [GeV]

E*

s [GeV]

b [fm]

x

b [fm]

x

  • A. S., A. R., M. K., Phys. Rev. C 95, 024908 (2017)
  • R. Hagedorn, CERN-71-12

W.D. Myers, Nucl. Phys. A

(Re)invented by A. Szczurek

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  • A. Rybicki et al., MESON 2018, 7-12 Jun 2018, Kraków, PL

dE dE

A.R., A.Szczurek, PRC 75, 2007, A.R., PoS (EPS-HEP2009)

Pb+Pb

  • A. R. and A. Szczurek,
  • Phys. Rev. C75 (2007)

054903

  • A. R.,

Acta Phys. Polon. B42 (2011) 867

Monte Carlo

d E = 0 fm dE = 1 fm d E = 0.5 fm d E = 1.5 fm

xF

dE ≈ 0.75 fm !

Monte Carlo

(c.m.s.)

xF = pL pL

beam

y = ybeam spectator velocity:

NA49 preliminary

  • A. R. and A. S.,
  • Phys. Rev. C75 (2007)

054903

Charged spectators (EM field) Repulsion ( for π+ ) Attraction ( for π− )

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  • A. Rybicki et al., MESON 2018, 7-12 Jun 2018, Kraków, PL

Pb+Pb

  • A. R.,

Acta Phys. Polon. B42 (2011) 867

S t

√sNN = 7.7 GeV _

Directed flow: v1 = < cos( φ−ΨRP ) > dE ≈ 0.75 fm

preliminary

y = ybeam

space-time evolution

  • f particle production (!)

dE

dE ≈ 3 fm

preliminary preliminary

y = ybeam

  • A. R.,

Acta Phys. Polon. B42 (2011) 867

spectator velocity:

NA49 preliminary

  • L. Adamczyk et al.

STAR, Phys. Rev. Lett. 112, (2014) 162301.

  • A. R. and A. S.,
  • Phys. Rev. C87

(2013) 054909.

  • A. R., APPB 46 (2015) 3, 737.

A.R. et al., APP Supp. 9 (2016) 303 and references therein

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28

  • A. Rybicki et al., MESON 2018, 7-12 Jun 2018, Kraków, PL

Pb+Pb

  • A. R.,

Acta Phys. Polon. B42 (2011) 867

S t

dE ≈ 0.75 fm

preliminary

y = ybeam

space-time evolution

  • f particle production (!)

dE

preliminary preliminary

t = tE dE

_

dE ≈ 3 fm

y/ybeam

“ELECTRO- MAGNETIC”

Work in progress

Original plot from:

  • K. Aamodt et al.

(ALICE Collab.),

  • Phys. Lett. B 696

(2011) 328

y = 0 y = ybeam spectator velocity:

NA49 preliminary A.R. et al., APP Supp. 9 (2016) 303 and references therein