A simultaneous unbinned differential cross section measurement of twenty-four $Z$+jets kinematic observables with the ATLAS detector

The ATLAS collaboration Aad, Georges ; Aakvaag, Erlend ; Abbott, Braden Keim ; et al.
Phys.Rev.Lett. 133 (2024) 261803, 2024.
Inspire Record 2791852 DOI 10.17182/hepdata.153189

$Z$ boson events at the Large Hadron Collider can be selected with high purity and are sensitive to a diverse range of QCD phenomena. As a result, these events are often used to probe the nature of the strong force, improve Monte Carlo event generators, and search for deviations from Standard Model predictions. All previous measurements of $Z$ boson production characterize the event properties using a small number of observables and present the results as differential cross sections in predetermined bins. In this analysis, a machine learning method called OmniFold is used to produce a simultaneous measurement of twenty-four $Z$+jets observables using $139$ fb$^{-1}$ of proton-proton collisions at $\sqrt{s}=13$ TeV collected with the ATLAS detector. Unlike any previous fiducial differential cross-section measurement, this result is presented unbinned as a dataset of particle-level events, allowing for flexible re-use in a variety of contexts and for new observables to be constructed from the twenty-four measured observables.

26 data tables

Differential cross-section in bins of dimuon $p_\text{T}$. The actual measurement is unbinned and available with examples at <a href="https://gitlab.cern.ch/atlas-physics/public/sm-z-jets-omnifold-2024">gitlab.cern.ch/atlas-physics/public/sm-z-jets-omnifold-2024</a>

Differential cross-section in bins of dimuon rapidity. The actual measurement is unbinned and available with examples at <a href="https://gitlab.cern.ch/atlas-physics/public/sm-z-jets-omnifold-2024">gitlab.cern.ch/atlas-physics/public/sm-z-jets-omnifold-2024</a>

Differential cross-section in bins of leading muon $p_\mathrm{T]$. The actual measurement is unbinned and available with examples at <a href="https://gitlab.cern.ch/atlas-physics/public/sm-z-jets-omnifold-2024">gitlab.cern.ch/atlas-physics/public/sm-z-jets-omnifold-2024</a>

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Coherent diffractive photoproduction of $\rho^{0}$ mesons on gold nuclei at RHIC

The STAR collaboration Adamczyk, L. ; Adkins, J.K. ; Agakishiev, G. ; et al.
Phys.Rev.C 96 (2017) 054904, 2017.
Inspire Record 1515028 DOI 10.17182/hepdata.101354

The STAR Collaboration reports on the photoproduction of $\pi^+\pi^-$ pairs in gold-gold collisions at a center-of-mass energy of 200 GeV/nucleon-pair. These pion pairs are produced when a nearly-real photon emitted by one ion scatters from the other ion. We fit the $\pi^+\pi^-$ invariant mass spectrum with a combination of $\rho$ and $\omega$ resonances and a direct $\pi^+\pi^-$ continuum. This is the first observation of the $\omega$ in ultra-peripheral collisions, and the first measurement of $\rho-\omega$ interference at energies where photoproduction is dominated by Pomeron exchange. The $\omega$ amplitude is consistent with the measured $\gamma p\rightarrow \omega p$ cross section, a classical Glauber calculation and the $\omega\rightarrow\pi^+\pi^-$ branching ratio. The $\omega$ phase angle is similar to that observed at much lower energies, showing that the $\rho-\omega$ phase difference does not depend significantly on photon energy. The $\rho^0$ differential cross section $d\sigma/dt$ exhibits a clear diffraction pattern, compatible with scattering from a gold nucleus, with 2 minima visible. The positions of the diffractive minima agree better with the predictions of a quantum Glauber calculation that does not include nuclear shadowing than with a calculation that does include shadowing.

13 data tables

The $\pi^+\pi^-$ invariant-mass distribution for all selected $\pi\pi$ candidates with $p_T~<~100~\textrm{MeV}/c$.

The ratio $|B/A|$ of amplitudes of nonresonant $\pi^+\pi^-$ and $\rho^0$ mesons in the present STAR analysis.

The ratio $|B/A|$ of amplitudes of nonresonant $\pi^+\pi^-$ and $\rho^0$ mesons in the previous STAR analysis, Phys. Rev. C 77 034910 (2008).

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Cross-sections for deuterium, tritium, and helium production in p p collisions at s = 1.8-TeV

Alexopoulos, T. ; Anderson, E.W. ; Biswas, N.N. ; et al.
Phys.Rev.D 62 (2000) 072004, 2000.
Inspire Record 536253 DOI 10.17182/hepdata.22220

We present the results of a search for the production of light elements in p¯p collisions at the Fermilab Tevatron collider. Momentum, time of flight, and dE/dx measurements are used to distinguish nuclei from elementary particles. A production ratio for deuterium to hydrogen is calculated and compared to the primordial value of the big bang model. Some evidence for tritium is found and none for helium isotopes.

3 data tables

Invariant cross section and cross section per unit rapidity interval for deuterium and anti-deuterium production.

Independent measurement of the proton or anti-proton production cross section (K Gulbrandsen, Senior Thesis, University of Wisconsin-Madison 1998).

Measured cross sections for tritium production.