φ and ω resonance decay modes Georgy Sharkov ITEP

φ and ω resonance decay modes

Georgy Sharkov

ITEP

19.04.23 G. Sharkov ITEP FRRC 2

Phase diagram of nuclear matter

NICA

,ω resonancesIf resonance decays before kinetic freeze-out Possible rescattering of hadronic daughters Reconstruction probability decrease for hadronic mode

ω(782) π+ π- π0 B.R. 0.89 (c = 23 fm)

ω(782) π+ π- B.R. 0.017

ω(782) π0 B.R. 0.089

ω(782) e+e- B.R. 0.000072

φ(1020) K+ K- B.R. 0.49 (c = 44 fm)

φ(1020) η B.R. 0.013

φ(1020) e+e- B.R. 0.000297

A.V. Stavinsky, Acta Phys. Polon B40; 1179-1184, 2009

hadrons

quarks&gluons

with &without QGP

t


Model

l

l0li

φη η

hadronization Kinetic freeze-out

l0~cτβ/√(1-β2) ~~(β=1/3 for this estimate)~~15fm(for φ) & 8fm(for ω)

li~2fm for any hadron & 1fmfor any pair of hadrons


• Upper line – lepton mode

φ

ω

Splitting – two hadron and hadron-photon modes

l,fm

l -decay products trajectory length within matter

β= 1/3

Model


Is it really possible measurement?

• Existing data from PHENIX& STAR– B– B– B– B

φ e+e-

φ K+K-

+-,

φ η

19.04.23 8

Φ(1020) K+ K- B.R. 0.49 c = 44 fm

Φ(1020) e+e- B.R. 0.000296 c = 44 fm

STAR Preliminary

d+Au

Au+Au

√sNN = 200 GeV

√sNN = 200 GeV

PHENIX

PHENIX

Φ K+ K-

Φ e+e-


ω(782) π+ π- π0 B.R. 0.89 c = 23 fm

ω(782) π0 B.R. 0.089 c = 23 fm

η(547) π+ π- π0 B.R. 0.23 c = 167225 fm

Au+Au

p+p

p+p

√sNN = 200 GeV

PHENIX

PHENIX

PHENIXω π0

ω π0

η,ω π+ π- π0


Φ Production K+K- and e+e-

• The leptonic channel yield is a little higher than hadronic channel• More accurate measurement is required to confirm whether there is

branch ratio modification

e+e-

K+K-


10K AuAu@25AGeV EPOS events

dN

/dIM

, 1/0

.1M

eV


dN

/dIM

, 1/0

.1M

eV

e+e-, π+π- Invariant mass

ω→π+π-

ω→e+e-

CBM simulationInput info

PLUTO generator (generates one particle from 25AGeV AuAu artificial fireball)

104 events for each resonance decay mode Setup: Target, Magnet, MVD, STS, RICH, TOF, TRD,

ECAL(FullMC) CBMROOT (DEC08), standard cuts


φ and ω in CBM


acceptance


Mean 0.7791Sigma 0.0101

Mean 1.01701Sigma 0.0101

•27% of φ reconstructed•28% of ω reconstructed

IM e+e- ,GeV/c2 ,GeV/c2


• 14% of φ reconstructed

Mean 1.0198Sigma 0.0039

Conclusions

• Comparison of vector mesons decay modes is proposed to study @ CBM

• AuAu collisions simulated using EPOS– Hadronic and leptonic modes– mixed modes (ω→πoγ; φ→ηγ): combinatorics

• PLUTO e+e-(ω , φ), K+K-(ω, φ) simulated and reconstructed in CBMROOT

• AuAu collisions reconstruction in CBMROOT– Under way


2006 UrQMD generator & cumulativeprocesses CBM simulation meeting

Direct photons analysisDirect photons analysis

100 105 110 115 1201

10

210

310

UrQMD AuAu c$ntral 25 AG$v

UrQMD code

f1(1285)

a1(1260)

K*

η'ω

"hm, yes photons are mesons in urqmd.however, photons should not be calculated within the urqmd, butexplicitely outside with a different code.everybody should ignore all processes with photons involved.we will move them out of the model in the next version.

cheers,Marcus Bleicher"

Re: [URQMD] ftn15 (fwd)

•Only from decay

•2 γγ elastic scatterings(?!)


Formulas

})0}(/exp{*

)({

)/1

}/exp{

/1

}/exp{(*

]))(}exp{1)[(}exp{

}/(exp{*

0

00

0

/

0

/)(

000

0

0

ii

ii

i

i

ii

ll lxl

ii

ii

lllB

lB

ll

ll

ll

llB

l

yd

l

y

l

xd

l

x

llBWi

Stavinskiy,ITEP,10.06.08


Electron, hadron and photon in PHENIX•PHENIX acceptance -0.35 < η < 0.35 2 x 90°in azimuthal angle for two arms• Event selection BBC

•Electron ID RICH EMCal

Momentum Electron ID

e+

e-

Momentum Hadron ID

K+

K-

•photon ID EMCal

•Hadron ID TOF EMCal-TOF

e+e-

K+K- +-,

Energy

Momentum Hadron ID


Extended K+K- analysis

candidates

Double ID analysis

no ID analysis

Single ID analysis

candidates

candidates

K+

K+ or K-

K-

h+ h-

h+ or h-

• K+K- measurements have been extended to both higher and lower pT using new methods, i.e. no kaon ID and single kaon ID methods.•The three independent kaon analyses are consistent with each other.

d+Au0-20%

p+p

　　 No ID　　 Single ID　　 Double ID　　

M.B.

Consistency between K+K- and e+e-

In p+p, spectra of e+e- and K+K- show reasonable agreement!

d+Au0-20%

p+p

　　 No ID　　 Single ID　　 Double ID　　 e+e-

M.B.


e+e- AuAu MB e+e- 20-40% x 10-3 e+e- 40-92% x 10-1 K+K- AuAu MB (no PID)K+K- AuAu MB (double PID) K+K- AuAu MB (PRC72 014903) K+K- 20-40% x 10-3 (double PID)K+K- 40-92% x 10-1 (double PID) K+K- 40-92% x 10-1 (PRC72 014903)

Errors are too large to make any clear statement about the comparison of spectra for e+e- and

40-92%20-40%

Au+Au

Spectra comparison between e+e- and K+K-

M.B.


Yield comparison between e+e- and K+K- Question 1’: Have we observed changes of yield between e+e- and K+K- ?

Have we observed changes of spectra between e+e- and K+K- ?

Comparison of integrated yield is not enough, becausemass modification effects depend on the pT region.Low pT mesons tend to decay inside the hot/dense matter

Now, we should ask

In addition,To determine the integrated yield, an extrapolation to lower pT is needed. There is a large uncertainty in the calculation.

Thus, pT-dependent information is essential for comparison.

Low pT

High pT


What is the difference?• Modes absorbtion vs Mass modification

– Standard mesons vs modified mesons – φ→KK & φ→η

• Modes absorbtion vs K/K* ratio– Lepton modes vs thermal model – Hadron stage vs equilibrium stage

• Modes absorbtion vs both other approaches– Internal cross-check - 3 modes



• ω photoproducton on nuclear targets (ELSA) M.Kotulla et al., ArXiv: nucl-ex/08020980

σωN ≈ 70 mb (in nuclear medium, 0.5 < P <1.6 GeV/c)

σωN ≈ 25 mb (in free space - the model calculations)

photoproducton on nuclear targets T.Ishikawa et al., Phys.Lett.B608,215,(2005)

σφN= 35 ± 14 mb (in nuclear medium)

σφN ≈ 10 mb (in free space)

“φ-puzzle”

Real σMN in matter can differ from that in free space

photoproducton on nuclear targets


Measurements of in wide pT range

Spectra show good agreement among several decay channels.

pT spectra of are measured for several decay modes in d+Au and p+p.

p+pd+Au

0 dAu MB (PRC75 151902)0+- dAu MB(PRC75 151902)e+e- pp MB (PHENIX preliminary)0 pp MB (PRC75 151902)0+- pp MB(PRC75 151902)0 pp ERT (PHENIX preliminary)0+- pp ERT (PHENIX preliminary)

Branching ratiosBranching ratios as anas an instrument for density integral instrument for density integral measurements measurements

mesons mesons mesonsmesons)) new source of informationnew source of information

Interplay between different ALICE subdetectors(?)Interplay between different ALICE subdetectors(?)


Why ?(common part)

Themeson was proposed in the middle of 80’(Koch,Muller,Rafelski PR142,ShorPRL54) as one of the most promising QGP messengers because of the following reasons:– an enhancement of –meson, as well as other strange

hadrons in QGP phase– interaction cross section is small and will keep

information about the early hot and dense phase– meson spectrum is not distorted by feeddown from

resonance decays– strangeness local conservation for


φ and ω resonance decay modes Georgy Sharkov ITEP

Documents

Transcript of φ and ω resonance decay modes Georgy Sharkov ITEP