Frank Geurts
· ProfessorVerifiedRice University · Physics
Active 1996–2025
About
Frank Geurts is a Professor of Physics and Astronomy at Rice University in Houston, Texas. He earned his Ph.D. from Utrecht University in the Netherlands in 1998, working on light meson production in ultrarelativistic heavy-ion collisions at the WA98 experiment at CERN's SPS accelerator. His research focuses on relativistic heavy-ion physics and high-energy nuclear physics. Geurts has extensive experience working on major experimental collaborations, including the STAR experiment at Brookhaven National Laboratory, where he has served as co-convener of the Light Flavor Spectra Physics Working group, Physics Analysis Coordinator, and deputy spokesperson. He has also contributed to the CMS Collaboration at CERN, co-leading the online software group for the Endcap Muon detector systems and managing the subsystem of the Endcap Timing Layer for the CMS MTD detector. Geurts was involved in the particle identification working group for the ATHENA detector proposal at the Electron-Ion Collider, which later merged into the ePIC collaboration. Since re-joining Rice University as a faculty member in 2008, he leads the Experimental Relativistic Heavy Group.
Research topics
- Physics
- Particle physics
- Nuclear physics
- Quantum mechanics
- Astrophysics
- Computer Science
- Optics
- Statistics
- Engineering
- Artificial Intelligence
- Mathematics
- Algorithm
- Astronomy
- Atomic physics
- Mathematical analysis
- Mechanics
- Geography
- Mechanical engineering
- Economics
- Geometry
Selected publications
Physical Review Letters · 2025-07-18 · 25 citations
articleWe report precision measurements on cumulants (C_{n}) and factorial cumulants (κ_{n}) of (net) proton number distributions up to fourth order in Au+Au collisions over center-of-mass energies sqrt[s_{NN}]=7.7-27 GeV from phase II of the Beam Energy Scan program at RHIC. (Anti)protons are selected at midrapidity (|y|<0.5) within a transverse momentum range of 0.4<p_{T}<2.0 GeV/c. Relative to various noncritical-point model calculations and peripheral collision 70%-80% data, the net proton C_{4}/C_{2} measurement in 0%-5% collisions shows a minimum around 19.6 GeV for significance of deviation at ∼2-5σ. A minimum in C_{4}/C_{2} with respect to a noncritical baseline is expected to be a characteristic feature of the signature associated with a critical point in the QCD phase diagram. In addition, deviations from noncritical baselines around the same collision energy region are also seen in proton factorial cumulant ratios, especially in κ_{2}/κ_{1} and κ_{3}/κ_{1}. Dynamical model calculations including a critical point are called for in order to understand these precision measurements.
Physical review. D/Physical review. D. · 2025-06-23
articleOpen accessWe report measurements of <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:mrow><a:mi mathvariant="normal">ϒ</a:mi><a:mo stretchy="false">(</a:mo><a:mn>1</a:mn><a:mi>S</a:mi><a:mo stretchy="false">)</a:mo></a:mrow></a:math>, <f:math xmlns:f="http://www.w3.org/1998/Math/MathML" display="inline"><f:mi mathvariant="normal">ϒ</f:mi><f:mo stretchy="false">(</f:mo><f:mn>2</f:mn><f:mi>S</f:mi><f:mo stretchy="false">)</f:mo></f:math> and <k:math xmlns:k="http://www.w3.org/1998/Math/MathML" display="inline"><k:mi mathvariant="normal">ϒ</k:mi><k:mo stretchy="false">(</k:mo><k:mn>3</k:mn><k:mi>S</k:mi><k:mo stretchy="false">)</k:mo></k:math> production in <p:math xmlns:p="http://www.w3.org/1998/Math/MathML" display="inline"><p:mi>p</p:mi><p:mo>+</p:mo><p:mi>p</p:mi></p:math> collisions at <r:math xmlns:r="http://www.w3.org/1998/Math/MathML" display="inline"><r:msqrt><r:mi>s</r:mi></r:msqrt><r:mo>=</r:mo><r:mn>500</r:mn><r:mtext> </r:mtext><r:mtext> </r:mtext><r:mi>GeV</r:mi></r:math> by the STAR experiment in year 2011, corresponding to an integrated luminosity <t:math xmlns:t="http://www.w3.org/1998/Math/MathML" display="inline"><t:msub><t:mi mathvariant="script">L</t:mi><t:mrow><t:mi>int</t:mi></t:mrow></t:msub><t:mo>=</t:mo><t:mn>13</t:mn><t:mtext> </t:mtext><t:mtext> </t:mtext><t:msup><t:mi>pb</t:mi><t:mrow><t:mo>−</t:mo><t:mn>1</t:mn></t:mrow></t:msup></t:math>. The results provide precise cross sections, transverse momentum (<w:math xmlns:w="http://www.w3.org/1998/Math/MathML" display="inline"><w:msub><w:mi>p</w:mi><w:mi mathvariant="normal">T</w:mi></w:msub></w:math>) and rapidity (<z:math xmlns:z="http://www.w3.org/1998/Math/MathML" display="inline"><z:mi>y</z:mi></z:math>) spectra, as well as cross section ratios for <bb:math xmlns:bb="http://www.w3.org/1998/Math/MathML" display="inline"><bb:msub><bb:mi>p</bb:mi><bb:mi mathvariant="normal">T</bb:mi></bb:msub><bb:mo><</bb:mo><bb:mn>10</bb:mn><bb:mtext> </bb:mtext><bb:mtext> </bb:mtext><bb:mi>GeV</bb:mi><bb:mo>/</bb:mo><bb:mi mathvariant="normal">c</bb:mi></bb:math> and <fb:math xmlns:fb="http://www.w3.org/1998/Math/MathML" display="inline"><fb:mo stretchy="false">|</fb:mo><fb:mi>y</fb:mi><fb:mo stretchy="false">|</fb:mo><fb:mo><</fb:mo><fb:mn>1</fb:mn></fb:math>. The dependence of the <jb:math xmlns:jb="http://www.w3.org/1998/Math/MathML" display="inline"><jb:mi mathvariant="normal">ϒ</jb:mi></jb:math> yield on charged particle multiplicity has also been measured, offering new insights into the mechanisms of quarkonium production. The data are compared to various theoretical models: the color evaporation model (CEM) accurately describes the <mb:math xmlns:mb="http://www.w3.org/1998/Math/MathML" display="inline"><mb:mi mathvariant="normal">ϒ</mb:mi><mb:mo stretchy="false">(</mb:mo><mb:mn>1</mb:mn><mb:mi>S</mb:mi><mb:mo stretchy="false">)</mb:mo></mb:math> production, while the color glass <rb:math xmlns:rb="http://www.w3.org/1998/Math/MathML" display="inline"><rb:mrow><rb:mi>condensate</rb:mi><rb:mo>+</rb:mo><rb:mtext>nonrelativistic</rb:mtext></rb:mrow></rb:math> quantum chromodynamics (<tb:math xmlns:tb="http://www.w3.org/1998/Math/MathML" display="inline"><tb:mrow><tb:mi>CGC</tb:mi><tb:mo>+</tb:mo><tb:mi>NRQCD</tb:mi></tb:mrow></tb:math>) model overestimates the data, particularly at low <vb:math xmlns:vb="http://www.w3.org/1998/Math/MathML" display="inline"><vb:msub><vb:mi>p</vb:mi><vb:mi mathvariant="normal">T</vb:mi></vb:msub></vb:math>. Conversely, the color singlet model (CSM) underestimates the rapidity dependence. These discrepancies highlight the need for further development in understanding the production dynamics of heavy quarkonia in high-energy hadronic collisions. The trend in the multiplicity dependence is consistent with CGC/saturation and string percolation models or <yb:math xmlns:yb="http://www.w3.org/1998/Math/MathML" display="inline"><yb:mi mathvariant="normal">ϒ</yb:mi></yb:math> production happening in multiple parton interactions modeled by 8.
Physical Review Letters · 2025-04-01 · 3 citations
erratumOpen accessThis corrects the article DOI: 10.1103/PhysRevLett.127.262301.
Onset of Constituent Quark Number Scaling in Heavy-Ion Collisions at RHIC
Physical Review Letters · 2025-07-17 · 10 citations
articlePartonic collectivity is one of the necessary signatures for the formation of quark-gluon plasma in high-energy nuclear collisions. Number of constituent quarks (NCQ) scaling has been observed for hadron elliptic flow v_{2} in top energy nuclear collisions at the Relativistic Heavy Ion Collider and the LHC, and this has been theoretically suggested as strong evidence for partonic collectivity. In this Letter, a systematic analysis of v_{2} of π^{±}, K^{±}, K_{S}^{0}, p, and Λ in Au+Au collisions at sqrt[s_{NN}]=3.2, 3.5, 3.9, and 4.5 GeV, with the STAR experiment at the Relativistic Heavy Ion Collider, is presented. NCQ scaling is markedly violated at 3.2 GeV, consistent with a hadronic-interaction dominated equation of state. However, as the collision energy increases, a gradual evolution to NCQ scaling is observed. This beam-energy dependence of v_{2} for all hadrons studied provides evidence for the onset of dominant partonic interactions by sqrt[s_{NN}]=4.5 GeV.
Physical Review Letters · 2025-09-10 · 3 citations
articleOpen accessHard-scattered partons ejected from high-energy proton-proton collisions undergo parton shower and hadronization, resulting in collimated collections of particles that are clustered into jets. A substructure observable that highlights the transition between the perturbative and nonperturbative regimes of jet evolution in terms of the angle between two particles is the two-point energy correlator (EEC). In this Letter, the first measurement of the EEC at RHIC is presented, using data taken from 200 GeV p+p collisions by the STAR experiment. The EEC is measured both for all the pairs of particles in jets and separately for pairs with like and opposite electric charges. These measurements demonstrate that the transition between perturbative and nonperturbative effects occurs within an angular region that is consistent with expectations of a universal hadronization regime that scales with jet momentum for a given initiator flavor. Additionally, a deviation from Monte Carlo predictions at small angles in the charge-selected sample could result from mechanics of hadronization not fully captured by current models.
Temperature measurement of Quark-Gluon plasma at different stages
Nature Communications · 2025-10-14 · 9 citations
articleOpen accessAbstract In a Quark-Gluon Plasma (QGP), the fundamental building blocks of matter, quarks and gluons, are under extreme conditions of temperature and density. A QGP could exist in the early stages of the Universe, and in various objects and events in the cosmos. The thermodynamic and hydrodynamic properties of the QGP are described by Quantum Chromodynamics (QCD) and can be studied in heavy-ion collisions. Despite being a key thermodynamic parameter, the QGP temperature is still poorly known. Thermal lepton pairs ( e + e − and μ + μ − ) are ideal penetrating probes of the true temperature of the emitting source, since their invariant-mass spectra suffer neither from strong final-state interactions nor from blue-shift effects due to rapid expansion. Here we measure the QGP temperature using thermal e + e − production at the Relativistic Heavy Ion Collider (RHIC). The average temperature from the low-mass region (in-medium ρ 0 vector-meson dominant) is (2.01 ± 0.23) × 10 12 K, consistent with the chemical freeze-out temperature from statistical models and the phase transition temperature from Lattice QCD. The average temperature from the intermediate mass region (above the ρ 0 mass, QGP dominant) is significantly higher at (3.25 ± 0.60) × 10 12 K. This work provides essential experimental thermodynamic measurements to map out the QCD phase diagram and understand the properties of matter under extreme conditions.
Physical Review Letters · 2025-03-31 · 6 citations
erratumOpen accessThis corrects the article DOI: 10.1103/PhysRevLett.126.092301.
Differential cross section measurements for the production of top quark pairs and of additional jets using dilepton events from pp collisions at $$ \sqrt{s} $$ = 13 TeV
OSTI OAI (U.S. Department of Energy Office of Scientific and Technical Information) · 2025 · 8 citations
- Physics
- Particle physics
- Nuclear physics
A bstract Differential cross sections for top quark pair ( $$ \textrm{t}\overline{\textrm{t}} $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mi>t</mml:mi> <mml:mover> <mml:mi>t</mml:mi> <mml:mo>¯</mml:mo> </mml:mover> </mml:math> ) production are measured in proton-proton collisions at a center-of-mass energy of 13 TeV using a sample of events containing two oppositely charged leptons. The data were recorded with the CMS detector at the CERN Large Hadron Collider and correspond to an integrated luminosity of 138 fb − 1 . The differential cross sections are measured as functions of kinematic observables of the $$ \textrm{t}\overline{\textrm{t}} $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mi>t</mml:mi> <mml:mover> <mml:mi>t</mml:mi> <mml:mo>¯</mml:mo> </mml:mover> </mml:math> system, the top quark and antiquark and their decay products, as well as of the number of additional jets in the event. The results are presented as functions of up to three variables and are corrected to the parton and particle levels. When compared to standard model predictions based on quantum chromodynamics at different levels of accuracy, it is found that the calculations do not always describe the observed data. The deviations are found to be largest for the multi-differential cross sections.
Electric-charge-dependent directed flow splitting of produced quarks in Au+Au collisions
Physics Letters B · 2025-01-17
articleOpen accessWe report directed flow ( v 1 ) of multistrange baryons (Ξ and Ω) and improved v 1 data for K − , p ¯ , Λ ¯ and ϕ in Au+Au collisions at s NN = 27 and 200 GeV from the STAR experiment at the Relativistic Heavy Ion Collider (RHIC). We focus on particles whose constituent quarks are not transported from the incoming nuclei but instead are produced in the collisions. At intermediate impact parameters, we examine quark coalescence behavior for particle combinations with identical quark content, and search for any departure from this behavior (“splitting”) for combinations having non-identical quark content. Under the assumption of quark coalescence for produced quarks, the splitting strength appears to increase with the electric charge difference of the constituent quarks in the combinations, consistent with electromagnetic effect expectations.
Design of the ECCE detector for the Electron Ion Collider
Nuclear Instruments and Methods in Physics Research Section A Accelerators Spectrometers Detectors and Associated Equipment · 2025-01-29 · 5 citations
articleOpen accessThe EIC Comprehensive Chromodynamics Experiment (ECCE) detector has been designed to address the full scope of the proposed Electron Ion Collider (EIC) physics program as presented by the National Academy of Science and provide a deeper understanding of the quark–gluon structure of matter. To accomplish this, the ECCE detector offers nearly acceptance and energy coverage along with excellent tracking and particle identification. The ECCE detector was designed to be built within the budget envelope set out by the EIC project while simultaneously managing cost and schedule risks. This detector concept has been selected to be the basis for the EIC project detector.
Frequent coauthors
- 4829 shared
M. Titov
Institut de Recherche sur les Lois Fondamentales de l'Univers
- 4813 shared
G. Hamel de Monchenault
Université Paris-Saclay
- 4749 shared
M. Lethuillier
Institute of Nuclear Physics of Lyon
- 4466 shared
A. Rosowsky
Institut de Recherche sur les Lois Fondamentales de l'Univers
- 4235 shared
S. Perriès
Institute of Nuclear Physics of Lyon
- 4222 shared
F. Beaudette
Laboratoire Leprince-Ringuet
- 4222 shared
J. Andreä
Institut Pluridisciplinaire Hubert Curien
- 4177 shared
C. Collard
Institut Pluridisciplinaire Hubert Curien
Education
- 1998
Ph.D., Physics
Universiteit Utrecht
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