Production of φ Mesons as a Function of Multiplicity & Spherocity
(2017) FYSM60 20171Department of Physics
Particle and nuclear physics
- Abstract
- The purpose of this project is to further investigate whether the collective behavior observed in
high energy proton-proton (p-p) collision can be attributed to the formation of Quark-Gluon Plasma
(QGP). This is done by measuring the production rate of the strange φ meson in high multiplicity
p-p collisions at √sNN = 13 TeV. The high multiplicity p-p events are then divided into different
transverse spherocity bins, in order to gauge whether the φ production is dominated by events that
are geometrically characterized as jet-like or isotropic. The results, although leaving some questions to
be asked regarding the simulated detector efficiency, present a pronounced enhancement of φ mesons
in high multiplicity collisions, and further... (More) - The purpose of this project is to further investigate whether the collective behavior observed in
high energy proton-proton (p-p) collision can be attributed to the formation of Quark-Gluon Plasma
(QGP). This is done by measuring the production rate of the strange φ meson in high multiplicity
p-p collisions at √sNN = 13 TeV. The high multiplicity p-p events are then divided into different
transverse spherocity bins, in order to gauge whether the φ production is dominated by events that
are geometrically characterized as jet-like or isotropic. The results, although leaving some questions to
be asked regarding the simulated detector efficiency, present a pronounced enhancement of φ mesons
in high multiplicity collisions, and further state that the strangeness enhancement is dominated by
events with an overall isotropic shape. These findings suggest that Lund string-like models might
be inadequate at fully describing high multiplicity p-p collisions. It also gives further support to the
idea that the preferred mechanism of φ particle production might follow a statistical, hydrodynamical
model, through the formation of a QGP phase. (Less) - Popular Abstract (Swedish)
- Under detta projekt s˚a analyserades h¨ogenergetiska proton-proton kollisioner i syftet f¨or att b¨attre f¨orst˚a
hur den starka v¨axelverkan med hj¨alp av gluoner h˚aller ihop kvarkar, en av materians fundamentalpartiklar,
f¨or att bilda hadroner. Dessa h¨ogenergetiska protoner accelereras upp till 99 % av ljusets
hastighet med hj¨alp av partikelacceleratorn ”Large Hadron Collider” (LHC), innan de till slut kolliderar
mot varandra i speciellt kontruerade partikeldeteckorer. Kollisionerna ¨ar tillr¨ackligt kraftfulla f¨or att
kvarkarna momentant frig¨ors fr˚an sina hadroner, vilket g¨or det m¨ojligt att studera hur gluonerna och
kvarkarna interagerar med varandra.
Om kollisionen ¨ar tillr¨ackligt kraftfull s˚a kan en Kvark-Gluon... (More) - Under detta projekt s˚a analyserades h¨ogenergetiska proton-proton kollisioner i syftet f¨or att b¨attre f¨orst˚a
hur den starka v¨axelverkan med hj¨alp av gluoner h˚aller ihop kvarkar, en av materians fundamentalpartiklar,
f¨or att bilda hadroner. Dessa h¨ogenergetiska protoner accelereras upp till 99 % av ljusets
hastighet med hj¨alp av partikelacceleratorn ”Large Hadron Collider” (LHC), innan de till slut kolliderar
mot varandra i speciellt kontruerade partikeldeteckorer. Kollisionerna ¨ar tillr¨ackligt kraftfulla f¨or att
kvarkarna momentant frig¨ors fr˚an sina hadroner, vilket g¨or det m¨ojligt att studera hur gluonerna och
kvarkarna interagerar med varandra.
Om kollisionen ¨ar tillr¨ackligt kraftfull s˚a kan en Kvark-Gluon Plasma bildas. Kvark-gluon plasman
¨ar ett v¨aldigt kompakt och varmt materietillst˚and som f¨orh˚aller sig i termiskt och kemiskt ekvilibrium.
I en kvark-gluon plasma s˚a ¨ar kvarkarna och gluonerna inte bunda innuti hadroner, utan ist¨allet beter
sig som en kollektiv, perfekt (n¨astintill ingen viskositet) v¨atska. Plasman bildas bara under en v¨aldigt
kort tidstund innan det kyls ner. Efter nedkylningen s˚a ¨ar kvarkarna ˚aterigen bunda inom individuella
hadroner. Att kontinuerligt h˚alla kvark-gluon plasman vid korrekt tryck och temperatur skulle kr¨ava
enorma resurser, vilket g¨or det praktiskt om¨ojligt att direkt verifiera om plasman har bildats. Ist¨allet s˚a
unders¨oks hur andra producerade partiklar interagerar med kvark-gluon plasman, f¨or att b¨attre f¨orst˚a
hur den fungerar. Tecken p˚a att kvark-gluon plasma har bildats brukar vara att partiklarna i kollisionen
har ett kollektivt beteende, en ¨okad produktion av vissa parikelsorter och andra fenomen.
Ett problem uppstod dock n¨ar man m¨arkte att n˚agra av de fenomen som ans˚ags vara signaturer
av kvark-gluon plasman ¨aven hittades i kollisioner som man inte trodde var energetiska nog f¨or att
kunna bilda kvar-gluon plasma. D¨arefter ifr˚agasattes id´en om huruvida kvark-gluon plasma faktiskt
n˚agonsin bildats i en kontrollerad partikelkollision. Huvudsyftet med detta projekt ¨ar att unders¨oka hur
produktionen av φ mesonen, en partikel som tros har en ¨okad produktionshalt i en eventuell kvark-gluon
plasma, beter sig f¨or varierande proton-proton kollisioner av olika energigrader. (Less)
Please use this url to cite or link to this publication:
http://lup.lub.lu.se/student-papers/record/8921900
- author
- Nassirpour, Adrian LU
- supervisor
- organization
- course
- FYSM60 20171
- year
- 2017
- type
- H2 - Master's Degree (Two Years)
- subject
- language
- English
- id
- 8921900
- date added to LUP
- 2017-07-18 22:56:16
- date last changed
- 2017-07-18 22:56:16
@misc{8921900, abstract = {{The purpose of this project is to further investigate whether the collective behavior observed in high energy proton-proton (p-p) collision can be attributed to the formation of Quark-Gluon Plasma (QGP). This is done by measuring the production rate of the strange φ meson in high multiplicity p-p collisions at √sNN = 13 TeV. The high multiplicity p-p events are then divided into different transverse spherocity bins, in order to gauge whether the φ production is dominated by events that are geometrically characterized as jet-like or isotropic. The results, although leaving some questions to be asked regarding the simulated detector efficiency, present a pronounced enhancement of φ mesons in high multiplicity collisions, and further state that the strangeness enhancement is dominated by events with an overall isotropic shape. These findings suggest that Lund string-like models might be inadequate at fully describing high multiplicity p-p collisions. It also gives further support to the idea that the preferred mechanism of φ particle production might follow a statistical, hydrodynamical model, through the formation of a QGP phase.}}, author = {{Nassirpour, Adrian}}, language = {{eng}}, note = {{Student Paper}}, title = {{Production of φ Mesons as a Function of Multiplicity & Spherocity}}, year = {{2017}}, }