This is a tuning of the two Jimmy parameters PTJIM (MPI cut-off) and PRRAD = JMRAD(73) = JMRAD(93) (Proton/Antiproton radius). The pdf used for this tuning is MSTW's LO* mLOpdf. Further HERWIG-parameters were not touched. The energy dependence of PTJIM and the tuning results as well as the parameter sampling ranges (p_i,low/high) are given below. The exponent energy of the energy dependence is fixed. The functional form is the same as in Pythia.
CDF_2001_S4751469 ================= Field & Stuart Run I underlying event analysis. Status: VALIDATED Spires ID: 4751469 Spires URL: http://www.slac.stanford.edu/spires/find/hep/www?rawcmd=key+4751469 Experiment: CDF Tevatron Run 1 Year of publication: 2001 Authors: Andy Buckley <andy.buckley@durham.ac.uk> Description: The original CDF underlying event analysis, based on decomposing each event into a transverse structure with ``toward'', ``away'' and ``transverse'' regions defined relative to the azimuthal direction of the leading jet in the event. Since the toward region is by definition dominated by the hard process, as is the away region by momentum balance in the matrix element, the transverse region is most sensitive to multi- parton interactions. The transverse regions occupy $|\phi| \in [60\degree, 120\degree]$ for $|\eta| < 1$. The pT ranges for the leading jet are divided experimentally into the `min-bias' sample from 0--20 GeV, and the `JET20' sample from 18--49 GeV. Run details: ppbar QCD interactions at 1800 GeV. The leading jet is binned from 0--49 GeV, and histos can usually can be filled with a single generator run without kinematic sub-samples. References: Phys.Rev.D65:092002,2002 FNAL-PUB 01/211-E
CDF_2004_S5839831 ================= Transverse cone and 'Swiss cheese' underlying event studies Status: VALIDATED Spires ID: 5839831 Spires URL: http://www.slac.stanford.edu/spires/find/hep/www?rawcmd=key+5839831 Experiment: CDF Tevatron Run 2 Year of publication: 2004 Authors: Andy Buckley <andy.buckley@durham.ac.uk> Description: This analysis studies the underlying event via transverse cones of $R = 0.7$ at 90 degrees in \phi relative to the leading (highest E) jet, at sqrt(s) = 630 and 1800 GeV. This is similar to the 2001 CDF UE analysis, except that cones, rather than the whole central \eta range are used. The transverse cones are categorised as TransMIN and TransMAX on an event-by- event basis, to give greater sensitivity to the UE component. 'Swiss Cheese' distributions, where cones around the leading $n$ jets are excluded from the distributions, are also included for $n = 2, 3$. This analysis is useful for constraining the energy evolution of the underlying event, since it performs the same analyses at two distinct CoM energies. Run details: QCD events at sqrt(s) = 630 & 1800 GeV Several pTmin cutoffs are probably required to fill the profile histograms, e.g. 0 (min bias), 30, 90, 150 GeV at 1800 GeV; and 0 (min bias), 20, 90, 150 GeV } at 630 GeV References: Phys. Rev. D70, 072002 (2004) arXiv:hep-ex/0404004 - http://arxiv.org/abs/hep-ex/0404004
CDF_2008_LEADINGJETS ==================== CDF Run 2 underlying event in leading jet events Status: VALIDATED Spires ID: NONE Spires URL: http://www.slac.stanford.edu/spires/find/hep/www?rawcmd=key+NONE Experiment: CDF Tevatron Run 2 Year of publication: 2008 Authors: Hendrik Hoeth <hendrik.hoeth@cern.ch> Description: Rick Field's measurement of the underlying event in leading jet events. If the leading jet of the event is within $|\eta| < 2$, the event is accepted and ``toward'', ``away'' and ``transverse'' regions are defined in the same way as in the original (2001) CDF underlying event analysis. The leading jet defines the $\phi$ direction of the toward region. The transverse regions are most sensitive to the underlying event. Run details: ppbar QCD interactions at 1960 GeV. Particles with $c \tau > {}$10 mm should be set stable. Several $p_\perp^\text{min}$ cutoffs are probably required to fill the profile histograms. $p_\perp^\text{min} = {}$ 0 (min bias), 10, 20, 50, 100, 150 GeV. The corresponding merging points are at $p_T = $ 0, 30, 50, 80, 130, 180 GeV
D0_2004_S5992206 ================ Run II jet azimuthal decorrelation analysis Status: VALIDATED Spires ID: 5992206 Spires URL: http://www.slac.stanford.edu/spires/find/hep/www?rawcmd=key+5992206 Experiment: D0 Tevatron Run 2 Year of publication: 2004 Authors: Lars Sonnenschein <lars.sonnenschein@cern.ch> Description: Correlations in the azimuthal angle between the two largest pT jets have been measured using the D0 detector in ppbar collisions at 1960 GeV. The analysis is based on an inclusive dijet event sample in the central rapidity region. The correlations are determined for four different pT intervals. Run details: QCD events in ppbar interactions at sqrt(s) = 1960 GeV. References: Phys. Rev. Lett., 94, 221801 (2005) arXiv:hep-ex/0409040 - http://arxiv.org/abs/hep-ex/0409040