STAR detector

<h2 id="the-physics-of-star">The physics of STAR</h2>
<p>In the immediate aftermath of the <a href="/facts/Big_Bang/I5T1vTnv">Big Bang</a>, the expanding matter was so hot and dense that protons and neutrons could not exist. Instead, the early universe comprised a plasma of <a href="/facts/Quarks/hwuuVkV5">quarks</a> and <a href="/facts/Gluons/t6YH8I21">gluons</a>. In today's cool universe, quarks and gluons are <a href="/facts/Color_confinement/W3XjqMAS">confined</a> and exist only within composite particles (bound states) – the <a href="/facts/Hadrons/C0sd1zty">hadrons</a>, such as protons and neutrons. Collisions of heavy nuclei at sufficiently high energies allow physicists to study whether quarks and gluons become deconfined at high densities, and if so, what the properties of this matter (i.e. quark–gluon plasma) are.
</p><p>In particular, STAR studies the collective expansion of the hot quark-gluon matter, such as the <a href="/facts/Elliptic_flow/UW84K3Mo">elliptic flow</a>. This allows to extract the transport coefficients that characterize the quark-gluon matter, including the shear and bulk <a href="/facts/Viscosity/QLVfrdCz">viscosity</a>, and to investigate <a href="/facts/Macroscopic_quantum_phenomena/upqTn4Rp">macroscopic quantum phenomena</a>, such as the <a href="/facts/Chiral_magnetic_effect/gx3y6dGV">chiral magnetic effect</a>.
</p>
<h2 id="collaboration-governance">Collaboration governance</h2>
<p>The governance of STAR is via two branches:  the institutional Council which is run by a Chairperson elected from the Council ranks, and elected Spokesperson(s) and their management team.  The Spokesperson(s) represent the Collaboration in scientific, technical, and managerial concerns. The Council deals with general issues that concern the collaboration. Examples include the organization and governance of the Collaboration, adoption of bylaws and amendments thereto, the policy on admission of new members institutions to the Collaboration, and Policies for the Publication and Presentation of STAR Results.
</p><p>The term of the office of the Council Chair is nominally two years. The Council elects, a Spokesperson or a team of two Spokespersons who then serve at the discretion of the Council.  The normal term of office for the Spokesperson(s) is 3 years, and an individual is eligible to serve at most two consecutive terms as Spokesperson(s).
</p><p>The elected Spokesperson(s) and their team of Deputies, and the Council Chairs of STAR are listed below. The Institute listed indicates the institute the person was at when they held the position.
</p>
<h3>Spokespersons</h3>
<ul><li>2023-present  Spokespeople : Frank Geurts (Rice), Lijuan Ruan (BNL)
<ul><li>Deputies:  ShinIchi Esumi (Tsukuba), Qinghua Xu (Shandong)</li></ul></li>
<li>2020–2023  Spokespeople :  <a href="/facts/Helen_Caines/vH0Qd33L">Helen Caines</a> (Yale), Lijuan Ruan (BNL)
<ul><li>Deputies:  Kenneth Barish (UC Riverside), Xin Dong (LBNL)</li></ul></li>
<li>2017–2020  Spokespeople :  Helen Caines (Yale), Zhangbu Xu (BNL)
<ul><li>Deputies:  Jim Drachenberg (ACU), Frank Geurts (Rice)</li></ul></li>
<li>2014–2017 : Zhangbu Xu (BNL)
<ul><li>Deputies : Helen Caines (Yale), Renee Fatemi (UTK), Ernst Sichtermann (LBNL)</li></ul></li>
<li>2011–2014 : Nu Xu (LBNL)
<ul><li>Deputies:  James Dunlop (BNL), <a href="/facts/Bedangadas_Mohanty/8EResTIU">Bedangadas Mohanty</a> (VECC/NISER),  Scott Wissink (Indiana)</li></ul></li>
<li>2008–2011: Nu Xu (LBNL)
<ul><li>Deputies : James Dunlop (BNL), <a href="/facts/Olga_Evdokimov/AzVoQwoV">Olga Evdokimov</a> (UIC), Berndt Surrow (MIT)</li></ul></li>
<li>2005–2008 : Tim Hallman (BNL)
<ul><li>Deputies : Carl Gagliardi (Texas A&M), Hans Georg Ritter (LBNL), Helen Caines (Yale) (2007 - 2008)</li></ul></li>
<li>2002–2005 : Tim Hallman (BNL)
<ul><li>Deputies : Jim Thomas (LBNL), Steven Vigdor (Indiana)</li></ul></li>
<li>1991–2002 : <a href="/facts/John_Harris_(physicist)/YoLhoyxW">John Harris</a> (Yale)
<ul><li>Deputies : Rene Bellwied (Wayne State) (2001-2002), Tim Hallman (BNL) (1999-2000)</li></ul></li></ul>
<h3>Council Chairpersons</h3>
<ul><li>2021–present : Jana Bielčíková (NPI, CAS)</li>
<li>2016–2021 : Olga Evdokimov (UIC)</li>
<li>2014–2016 : Huan Huang (UCLA)</li>
<li>2009–2014 : <a href="/facts/Gary_Westfall/nv4NTX7z">Gary Westfall</a> (MSU)</li>
<li>2005–2008 : Hank Crawford (UC Berkeley)</li>
<li>2003–2005 : Bill Christie (BNL)</li>
<li>2000–2003 : Jay Marx (LBNL)</li></ul>
<h2 id="see-also">See also</h2>
<ul><li><a href="/facts/Breit%25E2%2580%2593Wheeler_process/Xma5K2bH">Breit–Wheeler process</a></li>
<li><a href="/facts/Vacuum_birefringence/vFb3RH9y">Vacuum birefringence</a></li></ul>

<h2 id="external-links">External links</h2>
<p><a href="https://inspirehep.net/experiments/1108784">STAR experiment</a> record on <a href="/facts/INSPIRE-HEP/CDEYl9E1">INSPIRE-HEP</a>
</p>

<h2 id="references">References</h2>

<ol>
<li id="fn:1"><p>Caines, Helen; et al. (STAR Collaboration) (2004). "An update from STAR—using strangeness to probe relativistic heavy ion collisions". Journal of Physics G: Nuclear and Particle Physics. 30 (1): S61 – S73. Bibcode:2004JPhG...30S..61C. doi:10.1088/0954-3899/30/1/005. ISSN 0954-3899. <a href="/wiki/Helen_Caines" target="_blank">/wiki/Helen_Caines</a> <a href="#fnref:1" class="footnote-back-ref">↩</a></p></li>
<li id="fn:2"><p>STAR webpage <a href="http://www.star.bnl.gov/" target="_blank">http://www.star.bnl.gov/</a> <a href="#fnref:2" class="footnote-back-ref">↩</a></p></li>
<li id="fn:3"><p>STAR Lite, education and outreach <a href="http://www.star.bnl.gov/lite/" target="_blank">http://www.star.bnl.gov/lite/</a> <a href="#fnref:3" class="footnote-back-ref">↩</a></p></li>
</ol>

STAR detector open-in-new

STAR detector