Download - Why x-t correlation may be important for HBT
![Page 1: Why x-t correlation may be important for HBT](https://reader035.vdocument.in/reader035/viewer/2022070405/56813f55550346895daa1bc4/html5/thumbnails/1.jpg)
Zi-Wei LinZi-Wei Lin Collective flow and QGP propertiesCollective flow and QGP properties 11/19/200311/19/2003
● Why x-t correlation may be important for HBT● Origin of a large&positive x-t correlation:
partonic? resonance decays? hadronic rescatterings?
● Can a (hydro-type) negative x-t correlation
survive decays/rescatterings in a transport model?
• Rout/Rside: from Gaussian fit vs from emission function
Strong and positive x-t correlation and its effect on Rout/Rside
Zi-Wei LinThe Ohio State University
![Page 2: Why x-t correlation may be important for HBT](https://reader035.vdocument.in/reader035/viewer/2022070405/56813f55550346895daa1bc4/html5/thumbnails/2.jpg)
Zi-Wei LinZi-Wei Lin Collective flow and QGP propertiesCollective flow and QGP properties 11/19/200311/19/2003
HBT Radii fromEmission function S(x,p) or correlation function C(q)
If source is Gaussian in space-time, then:
Rsource,ij=Rfit,ij
1) Curvature at q=0: 2) Often use 4-parameter fitfor C(q) w/o Coulomb effects:
Pratt,PRL84
Pratt,PRL84Wiedemann,PRC57
Dx,y=<x*y>-<x><y>
. 2
![Page 3: Why x-t correlation may be important for HBT](https://reader035.vdocument.in/reader035/viewer/2022070405/56813f55550346895daa1bc4/html5/thumbnails/3.jpg)
Zi-Wei LinZi-Wei Lin Collective flow and QGP propertiesCollective flow and QGP properties 11/19/200311/19/2003
Study HBT with a transport model
Advantage:freezeout in transport is natural as the mean free path grows too big compared with system size
How to relate to hydro calculations (Cooper-Frye formula at a sharp hypersurface is usually imposed)
![Page 4: Why x-t correlation may be important for HBT](https://reader035.vdocument.in/reader035/viewer/2022070405/56813f55550346895daa1bc4/html5/thumbnails/4.jpg)
Zi-Wei LinZi-Wei Lin Collective flow and QGP propertiesCollective flow and QGP properties 11/19/200311/19/2003
HIJINGenergy in strings and minijet partons
ZPC (Zhang's Parton Cascade)
Till Parton freezeout
ART (A Relativistic Transport model for hadrons)
A+A
Decay all resonances;Final particle spectra
Structure of AMPT modelwith String Melting
Fragment excited strings into partons
Coalescence into hadrons
![Page 5: Why x-t correlation may be important for HBT](https://reader035.vdocument.in/reader035/viewer/2022070405/56813f55550346895daa1bc4/html5/thumbnails/5.jpg)
Zi-Wei LinZi-Wei Lin Collective flow and QGP propertiesCollective flow and QGP properties 11/19/200311/19/2003
ZWL,Ko&Pal,PRL89
From Gaussian fits to 3-d correlation function C(q)
Au+Au at 130AGeV(b=0 fm)
![Page 6: Why x-t correlation may be important for HBT](https://reader035.vdocument.in/reader035/viewer/2022070405/56813f55550346895daa1bc4/html5/thumbnails/6.jpg)
Zi-Wei LinZi-Wei Lin Collective flow and QGP propertiesCollective flow and QGP properties 11/19/200311/19/2003
Why x-t correlation may be important?
Spatial-size x-t correlation duration-time
Magnitude and sign of x-t correlationare important for Rout, Rout/Rside, & extraction of duration-time
![Page 7: Why x-t correlation may be important for HBT](https://reader035.vdocument.in/reader035/viewer/2022070405/56813f55550346895daa1bc4/html5/thumbnails/7.jpg)
Zi-Wei LinZi-Wei Lin Collective flow and QGP propertiesCollective flow and QGP properties 11/19/200311/19/2003
Correlations in pion emission source: out-side out-t
<Xout (t)>
Positive and large, tends to reduce Rout Values: (17fm)**2 = 185 -2*168 + 431
SourceSpatial-size x-t correlation Duration time
ZWL,Ko&Pal,PRL89
Note:includes decays
![Page 8: Why x-t correlation may be important for HBT](https://reader035.vdocument.in/reader035/viewer/2022070405/56813f55550346895daa1bc4/html5/thumbnails/8.jpg)
Zi-Wei LinZi-Wei Lin Collective flow and QGP propertiesCollective flow and QGP properties 11/19/200311/19/2003
out-side out-t
K emission source (excludes decays):
ZWL&Ko,JPG29
Values: (3.4fm)**2 = 35 -2*22 + 20
K source
<Xout (t)>
also positive and large for K
![Page 9: Why x-t correlation may be important for HBT](https://reader035.vdocument.in/reader035/viewer/2022070405/56813f55550346895daa1bc4/html5/thumbnails/9.jpg)
Zi-Wei LinZi-Wei Lin Collective flow and QGP propertiesCollective flow and QGP properties 11/19/200311/19/2003
●Turn off decays to study HBT radiifrom the emission function
●Test hydro-like negative x-t correlationupon hadron formation in AMPT
![Page 10: Why x-t correlation may be important for HBT](https://reader035.vdocument.in/reader035/viewer/2022070405/56813f55550346895daa1bc4/html5/thumbnails/10.jpg)
Zi-Wei LinZi-Wei Lin Collective flow and QGP propertiesCollective flow and QGP properties 11/19/200311/19/2003
Pions at freezeout
xout
xsid
e
x
y
mostly partons
~surface emission ~volume emission
<xout> >0parton transverse flow
![Page 11: Why x-t correlation may be important for HBT](https://reader035.vdocument.in/reader035/viewer/2022070405/56813f55550346895daa1bc4/html5/thumbnails/11.jpg)
Zi-Wei LinZi-Wei Lin Collective flow and QGP propertiesCollective flow and QGP properties 11/19/200311/19/2003
x-t correlation for pions
Au+Au at 200AGeV (b=0 fm)
![Page 12: Why x-t correlation may be important for HBT](https://reader035.vdocument.in/reader035/viewer/2022070405/56813f55550346895daa1bc4/html5/thumbnails/12.jpg)
Zi-Wei LinZi-Wei Lin Collective flow and QGP propertiesCollective flow and QGP properties 11/19/200311/19/2003
Already present for quarksx-t correlation for pions
Au+Au at 200AGeV (b=0 fm)
![Page 13: Why x-t correlation may be important for HBT](https://reader035.vdocument.in/reader035/viewer/2022070405/56813f55550346895daa1bc4/html5/thumbnails/13.jpg)
Zi-Wei LinZi-Wei Lin Collective flow and QGP propertiesCollective flow and QGP properties 11/19/200311/19/2003
Effect of decays on source radii
Hadronic decays produce mt-dependence in Rout & Rside
![Page 14: Why x-t correlation may be important for HBT](https://reader035.vdocument.in/reader035/viewer/2022070405/56813f55550346895daa1bc4/html5/thumbnails/14.jpg)
Zi-Wei LinZi-Wei Lin Collective flow and QGP propertiesCollective flow and QGP properties 11/19/200311/19/2003
Rout/Rside from emission function
![Page 15: Why x-t correlation may be important for HBT](https://reader035.vdocument.in/reader035/viewer/2022070405/56813f55550346895daa1bc4/html5/thumbnails/15.jpg)
Zi-Wei LinZi-Wei Lin Collective flow and QGP propertiesCollective flow and QGP properties 11/19/200311/19/2003
Can an initial negative x-t correlation survive later?
Test negative x-t correlation from hydro models at RHIC energies
![Page 16: Why x-t correlation may be important for HBT](https://reader035.vdocument.in/reader035/viewer/2022070405/56813f55550346895daa1bc4/html5/thumbnails/16.jpg)
Zi-Wei LinZi-Wei Lin Collective flow and QGP propertiesCollective flow and QGP properties 11/19/200311/19/2003
large initial Rout/Rside ratio (source)
Initial hadrons:
![Page 17: Why x-t correlation may be important for HBT](https://reader035.vdocument.in/reader035/viewer/2022070405/56813f55550346895daa1bc4/html5/thumbnails/17.jpg)
Zi-Wei LinZi-Wei Lin Collective flow and QGP propertiesCollective flow and QGP properties 11/19/200311/19/2003
large final Rout/Rside ratio (source)
Negative x-t term becomes positive after hadronic scatterings
Final hadrons:
![Page 18: Why x-t correlation may be important for HBT](https://reader035.vdocument.in/reader035/viewer/2022070405/56813f55550346895daa1bc4/html5/thumbnails/18.jpg)
Zi-Wei LinZi-Wei Lin Collective flow and QGP propertiesCollective flow and QGP properties 11/19/200311/19/2003
Hardtke&Voloshin, PRC61
Radii are different from source or from Gaussian fit to C(Q)
![Page 19: Why x-t correlation may be important for HBT](https://reader035.vdocument.in/reader035/viewer/2022070405/56813f55550346895daa1bc4/html5/thumbnails/19.jpg)
Zi-Wei LinZi-Wei Lin Collective flow and QGP propertiesCollective flow and QGP properties 11/19/200311/19/2003
from source from C(Q) fit
big decrease for fitted Rout, Rout/Rside
AMPT: Au+Au at 200AGeV at b=0 fm, 3mb
Rout/Rside=1
![Page 20: Why x-t correlation may be important for HBT](https://reader035.vdocument.in/reader035/viewer/2022070405/56813f55550346895daa1bc4/html5/thumbnails/20.jpg)
Zi-Wei LinZi-Wei Lin Collective flow and QGP propertiesCollective flow and QGP properties 11/19/200311/19/2003
from source from C(Q) fit
With an initial negative x-t correlationat hadron formation
huge decrease for fitted Rout & Rout/Rside Rout/Rside >>1 ~=1
Rout/Rside=1
![Page 21: Why x-t correlation may be important for HBT](https://reader035.vdocument.in/reader035/viewer/2022070405/56813f55550346895daa1bc4/html5/thumbnails/21.jpg)
Zi-Wei LinZi-Wei Lin Collective flow and QGP propertiesCollective flow and QGP properties 11/19/200311/19/2003
●Strong and positive xout-t correlation term ●tends to reduce Rout and Rout/Rside.●already present at parton freezeout/hadron formation●An initial negative x-t correlation can lead to
large Rout/Rside (when evaluated from emission function)
●Rout/Rside: >1 from emission function
~=1 from Gaussian fits to C(Q).
●Even with an large initial negative x-t
(with Rout/Rside >>1 from the emission function)
●Further investigation is needed to find the reason.
HBT summary
![Page 22: Why x-t correlation may be important for HBT](https://reader035.vdocument.in/reader035/viewer/2022070405/56813f55550346895daa1bc4/html5/thumbnails/22.jpg)
Zi-Wei LinZi-Wei Lin Collective flow and QGP propertiesCollective flow and QGP properties 11/19/200311/19/2003
![Page 23: Why x-t correlation may be important for HBT](https://reader035.vdocument.in/reader035/viewer/2022070405/56813f55550346895daa1bc4/html5/thumbnails/23.jpg)
Zi-Wei LinZi-Wei Lin Collective flow and QGP propertiesCollective flow and QGP properties 11/19/200311/19/2003
v2(pt) for AuAu at 130A GeV: eta (-0.3, 0.3), minimum bias (b=0-13 fm in AMPT)
ZWL&Ko,PRC65
![Page 24: Why x-t correlation may be important for HBT](https://reader035.vdocument.in/reader035/viewer/2022070405/56813f55550346895daa1bc4/html5/thumbnails/24.jpg)
Zi-Wei LinZi-Wei Lin Collective flow and QGP propertiesCollective flow and QGP properties 11/19/200311/19/2003
1) From emission function (10mb) for midrapidity charged pions, central 130AGeV:
![Page 25: Why x-t correlation may be important for HBT](https://reader035.vdocument.in/reader035/viewer/2022070405/56813f55550346895daa1bc4/html5/thumbnails/25.jpg)
Zi-Wei LinZi-Wei Lin Collective flow and QGP propertiesCollective flow and QGP properties 11/19/200311/19/2003
data corrected for Coulomb effects
![Page 26: Why x-t correlation may be important for HBT](https://reader035.vdocument.in/reader035/viewer/2022070405/56813f55550346895daa1bc4/html5/thumbnails/26.jpg)
Zi-Wei LinZi-Wei Lin Collective flow and QGP propertiesCollective flow and QGP properties 11/19/200311/19/2003
Fitted radius parameters vs parton cross sections
![Page 27: Why x-t correlation may be important for HBT](https://reader035.vdocument.in/reader035/viewer/2022070405/56813f55550346895daa1bc4/html5/thumbnails/27.jpg)
Zi-Wei LinZi-Wei Lin Collective flow and QGP propertiesCollective flow and QGP properties 11/19/200311/19/2003
Ratio from source >1
> ratio from fit (~=1)
![Page 28: Why x-t correlation may be important for HBT](https://reader035.vdocument.in/reader035/viewer/2022070405/56813f55550346895daa1bc4/html5/thumbnails/28.jpg)
Zi-Wei LinZi-Wei Lin Collective flow and QGP propertiesCollective flow and QGP properties 11/19/200311/19/2003
MT-scaling for fitted R?
Kaon:source radii~fitted radii
10 mb results
ZWL&Ko,JPG29
![Page 29: Why x-t correlation may be important for HBT](https://reader035.vdocument.in/reader035/viewer/2022070405/56813f55550346895daa1bc4/html5/thumbnails/29.jpg)
Zi-Wei LinZi-Wei Lin Collective flow and QGP propertiesCollective flow and QGP properties 11/19/200311/19/2003
Zi-Wei Lin
The Ohio State University
Summary:
We study two-pion interferometry at RHIC energies using a multi-phase transport (AMPT) transport model. Strong and positive x-t correlation at kinetic freezeout is present already at the end of the partonic stage, and it remains after hadronic decays and after hadronic interactions.This positive x-t term tends to reduce Rout/Rside when they are evaluated from the space-time widths of the emission source.Moreover, when they are evaluated from Gaussian fits to the 3-d correlation function C(Q), values of Rout/Rside are found to decrease in general and become consistent with one.
![Page 30: Why x-t correlation may be important for HBT](https://reader035.vdocument.in/reader035/viewer/2022070405/56813f55550346895daa1bc4/html5/thumbnails/30.jpg)
Zi-Wei LinZi-Wei Lin Collective flow and QGP propertiesCollective flow and QGP properties 11/19/200311/19/2003
x-y distributions at freezeout
![Page 31: Why x-t correlation may be important for HBT](https://reader035.vdocument.in/reader035/viewer/2022070405/56813f55550346895daa1bc4/html5/thumbnails/31.jpg)
Zi-Wei LinZi-Wei Lin Collective flow and QGP propertiesCollective flow and QGP properties 11/19/200311/19/2003
Xout-Xside distributions at freezeout
![Page 32: Why x-t correlation may be important for HBT](https://reader035.vdocument.in/reader035/viewer/2022070405/56813f55550346895daa1bc4/html5/thumbnails/32.jpg)
Zi-Wei LinZi-Wei Lin Collective flow and QGP propertiesCollective flow and QGP properties 11/19/200311/19/2003
Can an initial negative x-t correlation survive later?
Negative x-t term expected at RHIC energies from Cooper-Frye used in hydro models
Toy model: hadron formation at surface rt*rt+t*t=(10fm)^2
![Page 33: Why x-t correlation may be important for HBT](https://reader035.vdocument.in/reader035/viewer/2022070405/56813f55550346895daa1bc4/html5/thumbnails/33.jpg)
Zi-Wei LinZi-Wei Lin Collective flow and QGP propertiesCollective flow and QGP properties 11/19/200311/19/2003
![Page 34: Why x-t correlation may be important for HBT](https://reader035.vdocument.in/reader035/viewer/2022070405/56813f55550346895daa1bc4/html5/thumbnails/34.jpg)
Zi-Wei LinZi-Wei Lin Collective flow and QGP propertiesCollective flow and QGP properties 11/19/200311/19/2003
Negative x-t term becomes positive after hadronic scatterings
![Page 35: Why x-t correlation may be important for HBT](https://reader035.vdocument.in/reader035/viewer/2022070405/56813f55550346895daa1bc4/html5/thumbnails/35.jpg)
Zi-Wei LinZi-Wei Lin Collective flow and QGP propertiesCollective flow and QGP properties 11/19/200311/19/2003
from source from C(q) fit
With an initial negative x-t correlationat: rt*rt+t*t=(10fm)^2
![Page 36: Why x-t correlation may be important for HBT](https://reader035.vdocument.in/reader035/viewer/2022070405/56813f55550346895daa1bc4/html5/thumbnails/36.jpg)
Zi-Wei LinZi-Wei Lin Collective flow and QGP propertiesCollective flow and QGP properties 11/19/200311/19/2003
With an initial negative x-t correlationbut at a larger surface: rt*rt+t*t=(20fm)^2
![Page 37: Why x-t correlation may be important for HBT](https://reader035.vdocument.in/reader035/viewer/2022070405/56813f55550346895daa1bc4/html5/thumbnails/37.jpg)
Zi-Wei LinZi-Wei Lin Collective flow and QGP propertiesCollective flow and QGP properties 11/19/200311/19/2003
due to larger initial surfaceof hadron formation: rt*rt+t*t=(20fm)^2