1. Production of Phi meson at 62.4GeV AuAu Collisions
Outlines:
1.Dataset , cut & method
2.Centroid & Width
3.Correction Factor
4.Spectra
5.Conclusion
Shengli Huang
Vanderbilt University
Group Meeting Feb14
Shengli Huang

2. The dataset, cuts and methods
DataSet: 62.4GeV Au+Au:
full field: --
Centrality:0~83.7%
|VertexZ|<30cm
The total events~ 34M
Kaon selections:
Quality 31&63
Momemtum Cut
~ EMCal: mom<2.5GeV/c
~ TOFw: mom<4.0GeV/c
Ghost and intruder tracks are kicked out
Mixing event methods:
8 centrality bins
6 VertexZ bins
10 mixing events
Normalization methods:
1)Akiba:Nevents/Nmixevents
2)Hemmick:2*sqrt(N++N--)
3)Integral yield(m0>1.10GeV)
Group Meeting Feb14
Shengli Huang

3. The Phi signal Centroid & Width
Min-Bias
Fit Function: Breit-wigner
with Gaussian mass resolution
of 1.4MeV
Width:
4.61 ± 0.46(sta) ±0.58(sys)MeV
Centroid:
1.020±0.0002(sta) ±0.0009(sys)GeV
Consistent with PDG value
Group Meeting Feb14
Shengli Huang

4. The Centroid & Width @Centrality
The centroid and width of phi meson have not centrality
dependence
Group Meeting Feb14
Shengli Huang

5. Correction Factor(I)
Group Meeting Feb14
Shengli Huang

6. Correction Factor(II)
Embedding Results:
Cent K+ K-
K+K-
0~20%
0.921±0.070
0.889 ± 0.077
0.819 ±0.007
20~40%
0.980±0.062
0.961 ±0.064
0.942 ±0.008
40~83.7%
0.977 ±0.068
0.963 ±0.009
Run-by-Run: reference #123202
Group Meeting Feb14
Shengli Huang

7. Spectra The invariant yield of phi meson as a function of mT
at three different centrality
The error is statistic error
only. The systematic error
is about 3%. It mainly
come from different fit
region and normal methods
Fit function:
Group Meeting Feb14
Shengli Huang

8.
The 1/0.5Npartdn/dy at 62GeV AuAu is smaller than 200GeV AuAu
They both increase from peripheral collision and saturates at central
collision.
Group Meeting Feb14
Shengli Huang

9. T
The T slope of phi meson at 62GeV is smaller than 200GeV. They both do not show centrality difference.
Group Meeting Feb14
Shengli Huang

10. Conclusions
1.The production of phi in 62.4GeV Au+Au collision has been studied.
2.The centroid & width of phi meson do not show clear centrality dependence
3.The T slope &1/0.5*Npartdn/dy at 62GeV AuAu are smaller than 200GeV. At these two energy, the T does not show centrality dependence, while 1/0.5*Npartdn/dy has a little increase from peripheral to central collisions
Group Meeting Feb14
Shengli Huang

11. The Phi signal Centroid & Width
3.Integral:4.03 ± 0.44MeV
1.Akiba: 4.61±0.46MeV
Min-Bias
Width:
4.61 ± 0.46(sta) ±0.58(sys)MeV
Centroid:
1.020±0.0002(sta) ±0.0009(sys)GeV
Consistent with PDG value
2.Hemmick:4.93 ± 0.47MeV
Group Meeting Feb14
Shengli Huang