Access Type

Open Access Dissertation

Date of Award

January 2014

Degree Type


Degree Name



Physics and Astronomy

First Advisor

Sergei Voloshin


Since 2009, the Large Hadron Collider (LHC) at European Organization

for Nuclear Research (CERN) has been conducting experiments in $pp$,

Pb-Pb, as well as $p$-Pb collisions with the center of mass energy

ranging $\sqrt{{s}_{NN}}=0.9-5.05$~TeV. In this thesis, both,

estimates of background correlations in anisotropic flow, $v_1-v_5$,


in Pb-Pb collisions at

$\sqrt{{s}_{NN}}=2.76$~TeV, and azimuthally differential pion femtoscopy

of Pb-Pb collisions are reported.

Two particle azimuthal correlations are statistically the most precise

method of measuring anisotropic flow. The main drawback of this method

is its sensitivity to the non-flow correlations, which unlike real

flow, do not have geometrical origin. Non-flow contribution can be

estimated from two particle azimuthal correlations using $pp$ data.

Measurements of the non-flow contribution using the uQ method and

Scalar Product (SP) method are reported for $pp$ collisions at

$\sqrt{{s}_{NN}}=2.76$~TeV and $\sqrt{{s}_{NN}}=7$~TeV for the first

through fifth harmonics.

Femtoscopy of non-central heavy-ion collisions provides access to

information on the geometry of the effective pion-emitting source. In

particular, its shape can be studied by measuring femtoscopic radii as

a function of the emission angle relative to the collision plane of

symmetry. The first measurements of azimuthally differential

femtoscopy in Pb-Pb collisions at $\sqrt{{s}_{NN}}=2.76$~TeV are

reported and compared to results from RHIC experiments at lower

energies. Oscillations of the extracted radii versus the emission

angle are measured, and

$R_{side}$ and $R_{out}$

oscillations are found to be out of phase. The relative amplitude of

the $R_{side}$ oscillations decreases in more central collisions,

however always remains positive. This indicates that the source is

out-of-plane extended, similar to that observed at RHIC energies.

Results are compared to existing hydrodynamical and transport model


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