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New herwig7 underlying event tune: From RHIC to LHC energies

Umar Sohail Qureshi1,2,*, Luke Mozarsky3,4,†, Helen Caines3, Raghav Kunnawalkam Elayavalli2, and Isaac Mooney3,5

  • *Contact author: uqureshi@cern.ch
  • †Contact author: luke.mozarsky@cern.ch
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Phys. Rev. D 112, 116019 – Published 24 December, 2025

DOI: https://doi.org/10.1103/cnck-wtbh

Abstract

We present parameter sets corresponding to new underlying event tunes for the herwig7.3 Monte Carlo event generator. The existing herwig tunes are in good agreement with LHC data, however, they are not typically designed for center-of-mass energies below s=300  GeV. The tunes presented in this study can describe midrapidity data collected at the nominal RHIC energy of s=200  GeV as well as higher center-of-mass energies utilized by experiments at the LHC and Tevatron. The base “New Haven” tune is developed by fitting minimum-bias simulations of proton-proton (pp) collisions to midrapidity identified hadron and jet data from the STAR experiment. The “Nashville” tune includes a separate set of parameters developed by tuning to Tevatron proton-antiproton (pp¯) data at s=300, 900 and 1960 GeV from CDF, and LHC pp measurements from CMS at s=7  TeV, in addition to the STAR measurements. Both new tunes demonstrate significant improvements over the recommended default tune currently included in the latest version of herwig for minimum bias production. As such, we advocate using these tunes for future simulation studies at midrapidity by experimental collaborations at RHIC (STAR and sPHENIX) and the LHC (ALICE, ATLAS, and CMS).

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Phys. Rev. D 112, 116019– Published 24 December, 2025
  • Received 5 May 2025
  • Accepted 5 November 2025
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Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI. Funded by SCOAP3.

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