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The most precise top quark mass measurements use kinematic reconstruction methods, determining the top mass parameter of a Monte Carlo event generator m_{t}^{MC}. Because of hadronization and parton-shower dynamics, relating m_{t}^{MC} to a field theory mass is difficult. We present a calibration procedure to determine this relation using hadron level QCD predictions for observables with kinematic mass sensitivity. Fitting e^{+}e^{-} 2-jettiness calculations at next-to-leading-logarithmic and next-to-next-to-leading-logarithmic order to pythia 8.205, m_{t}^{MC} differs from the pole mass by 900 and 600 MeV, respectively, and agrees with the MSR mass within uncertainties, m_{t}^{MC}≃m_{t,1 GeV}^{MSR}.
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http://dx.doi.org/10.1103/PhysRevLett.117.232001 | DOI Listing |
Phys Rev Lett
August 2025
Frankfurt Institute for Advanced Studies FIAS, Frankfurt 60438, Germany.
Partonic 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.
View Article and Find Full Text PDFRep Prog Phys
August 2025
CERN, Geneva, Switzerland.
A search for resonances in top quark pair (tt-) production in final states with two charged leptons and multiple jets is presented, based on proton-proton collision data collected by the CMS experiment at the CERN LHC ats=13TeV, corresponding to 138 fb. The analysis explores the invariant mass of thett-system and two angular observables that provide direct access to the correlation of top quark and antiquark spins. A significant excess of events is observed near the kinematictt-threshold compared to the non-resonant production predicted by fixed-order perturbative quantum chromodynamics (pQCD).
View Article and Find Full Text PDFEur Phys J C Part Fields
June 2025
Theoretical Physics Division, Institute of High Energy Physics, Beijing, 100049 China.
We propose a method for probing CP-violation in the heavy (pseudo)scalar sector of an extended Higgs model, in which we make simultaneous use of the ( ) and interactions of a heavy Higgs state . The CP-even component of can be probed through the tree-level interaction, while the CP-odd component of can be probed if the final pair can be tested to form a state. We can then confirm CP-violation if both CP-even and CP-odd components of are discovered.
View Article and Find Full Text PDFPhys Rev Lett
June 2025
Institute for High Energy Physics, Austrian Academy of Sciences, Nikolsdorfergasse 18, A-1050 Vienna, Austria.
The top quark mass is a key parameter of the standard model, yet measuring it precisely at the Large Hadron Collider (LHC) is challenging. Inspired by the use of standard candles in cosmology, we propose a novel energy correlator-based observable, which directly accesses the dimensionless quantity m_{t}/m_{W}. We perform a Monte Carlo study to demonstrate the feasibility of the top mass extraction from Run 2, 3, and High-Luminosity LHC datasets.
View Article and Find Full Text PDFPhys Rev Lett
June 2025
CERN, Theoretical Physics Department, 1211 Geneva 23, Switzerland.
The current projected sensitivity on the electromagnetic coupling α_{em}(m_{Z}^{2}) represents a bottleneck for the precision electroweak program at FCC-ee. We propose a novel methodology to extract this coupling directly from Z-pole data. By comparing the differential distribution of electrons, muons, and positrons in the forward region, the approach achieves a projected statistical sensitivity below the 10^{-5} level, representing a significant improvement over other methods.
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