R. du Rietz
A5106181472- Nuclear physics research studies
- Quantum Chromodynamics and Particle Interactions
- Astronomical and nuclear sciences
- High-Energy Particle Collisions Research
- Particle physics theoretical and experimental studies
- Atomic and Molecular Physics
- Nuclear Physics and Applications
- Nuclear reactor physics and engineering
- Cold Fusion and Nuclear Reactions
- Advanced Chemical Physics Studies
- X-ray Spectroscopy and Fluorescence Analysis
- Rare-earth and actinide compounds
- Electron and X-Ray Spectroscopy Techniques
- Particle Detector Development and Performance
- Atomic and Subatomic Physics Research
- High Temperature Alloys and Creep
- Radioactive Decay and Measurement Techniques
- Radiopharmaceutical Chemistry and Applications
- Urological Disorders and Treatments
- Quantum chaos and dynamical systems
- Mechanisms of cancer metastasis
- Thermodynamic and Structural Properties of Metals and Alloys
- Superconducting Materials and Applications
- Medical Imaging Techniques and Applications
- Scientific Research and Discoveries
Australian National University
2011-2022
Florida State University
2022
Malmö University
2013-2021
China Institute of Atomic Energy
2007-2013
Lund University
2003-2009
Institute of Nuclear Physics
2005-2008
The University of Tokyo
2007
Tokyo University of Science
2007
Abilene Christian University
2007
Banaras Hindu University
2007
The centrality dependence of transverse momentum distributions and yields for ${\ensuremath{\pi}}^{\ifmmode\pm\else\textpm\fi{}},{K}^{\ifmmode\pm\else\textpm\fi{}},p$, $\overline{p}$ in $\text{Au}+\text{Au}$ collisions at $\sqrt{{s}_{NN}}=200\phantom{\rule{0.3em}{0ex}}\text{GeV}$ midrapidity are measured by the PHENIX experiment Relativistic Heavy Ion Collider. We observe a clear particle mass shapes spectra central below $\ensuremath{\sim}2\phantom{\rule{0.3em}{0ex}}\text{GeV}∕c$ ${p}_{T}$....
The anisotropy parameter (v(2)), the second harmonic of azimuthal particle distribution, has been measured with PHENIX detector in Au+Au collisions at sqrt[s(NN)]=200 GeV for identified and inclusive charged production central rapidities (|eta|<0.35) respect to reaction plane defined high (|eta|=3-4 ). We observe that v(2) mesons falls below (anti)baryons p(T)>2 GeV/c, marked contrast predictions a hydrodynamical model. A quark-coalescence model is also investigated.
Transverse momentum spectra of neutral pions in the range 1<pT<10 GeV/c have been measured at midrapidity by PHENIX experiment BNL RHIC Au+Au collisions sNN=200 GeV. The π0 multiplicity central reactions is significantly below yields same sNN peripheral and p+p scaled number nucleon-nucleon collisions. For most bin, suppression factor ∼2.5 pT=2 increases to ∼4–5 pT≈4 GeV/c. At larger pT, remains constant within errors. deficit already apparent semiperipheral smoothly with centrality.Received...
The PHENIX experiment has measured midrapidity ([FORMULA: SEE TEXT]) transverse momentum spectra of electrons as a function centrality in Au+Au collisions at [FORMULA: TEXT]. Contributions from photon conversions and light hadron decays, mainly Dalitz decays pi0 eta mesons, were removed. resulting nonphotonic electron are primarily due to the semileptonic hadrons carrying heavy quarks. Nuclear modification factors determined by comparison p+p collisions. A significant suppression high pT is...
Azimuthal correlations of jet-induced high-pT charged hadron pairs are studied at midrapidity in Au+Au collisions √sNN=200 GeV. The distribution jet-associated partner hadrons (1.0<pT<2.5 GeV/c) per trigger (2.5<pT<4.0 is found to vary with collision centrality, both shape and yield, indicating a significant effect the nuclear medium on jet fragmentation process.Received 1 July 2005DOI:https://doi.org/10.1103/PhysRevLett.97.052301©2006 American Physical Society
The PHENIX experiment at RHIC has measured charged hadron yields mid-rapidity over a wide range of transverse momentum (0.5 < p_T 10 GeV/c) in Au+Au collisions sqrt(s_NN)=200 GeV. data are compared to pi^zero measurements from the same experiment. For both hadrons and neutral pions, per nucleon-nucleon collision significantly suppressed central peripheral collisions. suppression sets gradually increases with increasing centrality Above 4-5 GeV/c p_T, constant almost identical pi^zeroes is...
The invariant differential cross section for inclusive neutral-pion production in p+p collisions at √s=200 GeV has been measured midrapidity (|η|<0.35) over the range 1<pT≲14 GeV/c by PHENIX experiment Relativistic Heavy Ion Collider. Predictions of next-to-leading order perturbative QCD calculations are consistent with these measurements. precision our result is sufficient to differentiate between prevailing gluon-to-pion fragmentation functions.Received 28 April...
The first measurement of direct photons in Au + collisions at (square root)S(NN) = 200 GeV is presented. photon signal extracted as a function the collision centrality and compared to next-to-leading order perturbative quantum chromodynamics calculations. yield shown scale with number nucleon-nucleon for all centralities.
The PHENIX experiment at the relativistic heavy ion collider (RHIC) has measured transverse energy and charged particle multiplicity midrapidity in $\mathrm{Au}+\mathrm{Au}$ collisions center-of-mass energies $\sqrt{{s}_{\mathrm{NN}}}=19.6,130$, $200\phantom{\rule{0.3em}{0ex}}\text{GeV}$ as a function of centrality. presented results are compared to measurements from other RHIC experiments lower energies. $\sqrt{{s}_{\mathrm{NN}}}$ dependence $dE{}_{T}/d\ensuremath{\eta}$...
We report on the yield of protons and antiprotons, as a function centrality transverse momentum, in Au+Au collisions at sqrt[s(NN)]=200 GeV measured midrapidity by PHENIX experiment BNL Relativistic Heavy Ion Collider. In central intermediate momenta (1.5<p(T)<4.5 GeV/c) significant fraction all produced particles are antiprotons. They show centrality-scaling behavior different from that pions. The pmacr;/pi p/pi ratios enhanced compared to peripheral Au+Au, p+p, e(+)e(-) collisions. This...
Inclusive transverse momentum spectra of $\ensuremath{\eta}$ mesons have been measured within ${p}_{T}=2--10\text{ }\text{ }\mathrm{GeV}/c$ at midrapidity by the PHENIX experiment in $\mathrm{Au}+\mathrm{Au}$ collisions $\sqrt{{s}_{NN}}=200\text{ }\mathrm{GeV}$. In central yields are significantly suppressed compared to peripheral $\mathrm{Au}+\mathrm{Au}$, $d+\mathrm{Au}$, and $p+p$ scaled corresponding number nucleon-nucleon collisions. The magnitude, centrality, ${p}_{T}$ dependence...
Background: The formation of superheavy elements by fusion two massive nuclei is severely inhibited the competing quasifission process.Purpose: Through extensive mass-angle distribution measurements, we map out systematic dependence characteristics as a function identity colliding nuclei.Methods: Australian National University's Heavy Ion Accelerator Facility and CUBE spectrometer have been used to measure distributions for 42 reactions forming heavy elements. Beam energies above their...
Below-barrier no-capture breakup measurements of the weakly bound $^{9}\mathrm{Be}$ nucleus, incident on targets ranging in atomic number from 62 to 83, have been carried out using a large-area high-resolution back-angle detector array. It is shown that three-body reconstructed reaction $Q$-value and relative energy fragments together reveal full dynamics mechanism, identifying all physical processes lead projectile-like nucleus. Contrasting with simple expectation direct into most...
The quasi-fission mechanism hinders fusion in heavy systems through breakup within zeptoseconds into two fragments with partial mass equilibration. Its dependence on the structure of both collision partners and final is a key question. Our original approach to combine an experimental measurement fragments' mass-angle correlations $^{40}$Ca$+^{238}$U microscopic quantum calculations. We demonstrate unexpected interplay between orientation prolate deformed $^{238}$U shell effects fragments. In...
Using a back-angle detector array covering 117° to 167°, coincidence measurements of breakup fragments at sub-barrier energies have enabled the complete characterisation processes in reactions 6,7Li with 208Pb. Those fast enough (∼10−22 s) affect fusion are identified through measured relative energy two fragments. The majority these prompt events triggered by transfer neutron from 6Li, and proton 7Li. These mechanisms, rather than following direct projectile excitation, should thus be...
The role of spherical quantum shells in the competition between fusion and quasi-fission is studied for reactions forming heavy elements. Measurements fission fragment mass distributions different leading to similar compound nuclei have been made near barrier. In general, more observed with non-magic nuclei. However, 40Ca + 208Pb reaction an exception, showing strong evidence quasi-fission, though both are doubly magic. Time-dependent Hartree–Fock calculations predict fast equilibration N/Z...
Coincidence measurements of breakup fragments were carried out for the ${}^{7}\text{Li}+{}^{144}\text{Sm}$ and ${}^{6,7}\text{Li}+{}^{207,208}\text{Pb}$,${}^{209}\text{Bi}$ reactions at sub-barrier energies. Breakup modes in ${}^{6,7}\text{Li}$ identified through reaction $Q$ values, time-scales each process inferred relative energy fragments. was found to be predominantly triggered by nucleon transfer, with $p$ pickup leading $\ensuremath{\alpha}+\ensuremath{\alpha}$ coincidences being...
Bose-Einstein correlations of identically charged pion pairs were measured by the PHENIX experiment at mid-rapidity in Au+Au collisions $\sqrt{s_{\rm NN}}$ = 200 GeV. The Bertsch-Pratt radius parameters determined as a function transverse momentum pair and centrality collision. Using \it{full} Coulomb correction, ratio $R_{\rm out}/R_{\rm side}$ is smaller than unity for $<k_{\rm T}>$ from 0.25 to 1.2 GeV/c all centralities. However, using recently developed partial correction methods, we...
Transverse single-spin asymmetries to probe the transverse-spin structure of proton have been measured for neutral pions and nonidentified charged hadrons from polarized proton-proton collisions at midrapidity s=200 GeV. The data cover a transverse momentum (pT) range 1.0–5.0 GeV/c 0.5–5.0 hadrons, Feynman-x value approximately zero. seen in this previously unexplored kinematic region are consistent with zero within errors few percent. In addition, inclusive hadron cross section 0.5<pT<7.0...
The PHENIX experiment has measured midrapidity transverse momentum spectra (0.4<p(T)<4.0 GeV/c) of single electrons as a function centrality in Au+Au collisions at sqrt[s(NN)]=200 GeV. Contributions from photon conversions and Dalitz decays light neutral mesons are by introducing thin (1.7% X0) converter into the acceptance statistically removed. subtracted nonphotonic electron primarily due to semileptonic hadrons containing heavy quarks, mainly charm lower p(T). For all centralities,...
Measurements of neutral pion (π0) production at midrapidity in √sNN=200 GeV Au+Au collisions as a function transverse momentum, pT, collision centrality, and angle with respect to reaction plane are presented. The data represent the final π0 results from PHENIX experiment for first RHIC run design center-of-mass energy. They include additional obtained using Level-2 trigger more than factor 3 increase statistics over previously published pT>6 GeV/c. We evaluate suppression yield high-pT π0's...
The inhibition of fusion by quasifission is crucial in limiting the formation superheavy elements collisions heavy nuclei. Time scales ∼10(-18) s inferred for fissionlike events from recent crystal blocking measurements were interpreted to show either that itself slower than previously believed, or fraction slow fusion-fission higher expected. New mass-angle distributions (48)Ti and (64)Ni bombarding W targets these reactions dominant process, typically occurring before system formed after...
We present the results of $\ensuremath{\phi}$ meson production in ${K}^{+}{K}^{\ensuremath{-}}$ decay channel from $\mathrm{Au}+\mathrm{Au}$ collisions at $\sqrt{{s}_{\mathit{NN}}}=200\phantom{\rule{0.3em}{0ex}}\mathrm{GeV}$ as measured midrapidity by PHENIX detector Brookhaven National Laboratory's Relativistic Heavy Ion Collider. Precision resonance centroid and width values are extracted a function collision centrality. No significant variation Particle Data Group accepted is observed,...