Philipe de Almeida Mota Takeshi Kodama (Ph.D. Advisor ... · Philipe de Almeida Mota Takeshi Kodama...

Initial Conditions Fluctuations and the Ridge

Philipe de Almeida MotaTakeshi Kodama (Ph.D. Advisor)

Instituto de F́ısica – UFRJ, Rio de Janeiro, Brasil

June 9, 2010

Ph. Mota, [email protected] (UFRJ) June 9, 2010 1 / 24

motivation

study the effects of initial condition fluctuation to the observables,specially azimuthal correlations throught the shadow effect [Hama’s talk]


lternative approach to Mach cone

medium modified by fast parton

supersonic parton generates shock waves in the medium which propagatethrought the medium and give rise to the correlation observedpros: possible extraction of in medium propertiescons: idealized, many dynamical effects act against the simple Mach conepicture


shadow effect

smooth initial condition plusgaussian tube


shadow effect

single particle distribution two particle correlation

dip at the tube position andshoulders around it

features dip at away side


smooth + 1 tube

single particledistribution

temperature profile t=7 fm

medium blocked by tube expansion which is much more explosive


smooth + 1 tube

3 particle correlation 2 particle correlation

dN123

d∆φ12∆φ13=∫

dφdN1

dφ(φ)

dN2

dφ(φ+ ∆φ12)

dN3

dφ(φ+ ∆φ13)


smooth + fluctuation

3 tubes, average over different events

average of correlation correlation of averages

C(∆φ) =∫

dφ⟨f1(φ)f2(φ+ ∆φ)

⟩−⟨f1(φ)

⟩⟨f2(φ+ ∆φ)

⟩Ph. Mota, [email protected] (UFRJ) June 9, 2010 8 / 24

smooth + fluctuation

3 particle correlation 3 particle cumulant


dependence on distance

2 particle cumulant particle spectra

strongly affects the cumulant but does not changes the spectrum


peripheral collisions

temperature profile temperature profile


peripheral colision

medium + shadow shadow


fluctuating initial conditions

applying hydro to an e-by-e basis one has to face the possibility ofnon-homogenous IC

it is interesting to study if the effect is not washed out by thedynamics (Mach cone)


Random Tubes Model

energy density profile

ε(x⊥; b) =N(b)∑

i

εtube(x⊥ −Ri⊥)

spatial probability

P(R⊥; b) ∝ εWN(R⊥; b)

tube energy density

εtube(x⊥) = εtube0 exp

( x2⊥

2(σtube)2

)

number of tubes

N(b) =N(0)

EWN(0)EWN(b)

tube energy density at origin

εtube0 =

12π(σtube)2

EWN(b)N(b)

model parameters σ and N0


random tubes

σtube = 0.7 fm N b=0 = 200 σtube = 0.35 fm N b=0 = 200

both for b = 0.4STAR (arXiv:0809.3769): 0–20%−→ b < 6.6 fm


azimuthal distribution (.4–1×2–3)


elliptic flow


spectrum


conclusions

shadow effect survives throuth 2-particle correlations

fluctuations should exist at RHIC

simple and robust description for the ridge

understanding of the physical role of the parameters

position of the minimum may be related to EoS throught (c2s)


perspectives

compare results with other approaches

understand the microscopic origin of the tubes

aplication to p+p at LHC

study c2s dependence

perform v3 subtraction

let σtube fluctuate

longitudinal dynamics


backup

v2 fluctuations


Philipe de Almeida Mota Takeshi Kodama (Ph.D. Advisor ... · Philipe de Almeida Mota Takeshi Kodama...

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