Transverse momentum dependent parton distributions (TMDs) are crucial to increase precision in the calculations of LHC observables that are sensitive to multiple soft gluon emissions and low-x effects. Collinear parton showers can resum the cross section to take into account large contributions at high orders in the strong coupling. However, in this case transverse momentum is not present in...
In this talk, we will present our novel approach, implemented in PYTHIA8, of including string shoving and forming ropes with strings in a special Lorentz frame, called parallel frame, where we have a pair of strings in symmetric geometry. We will discuss results to check if this formulation can achieve the particle production yields, namely strangeness enhancement, and their v_2 as seen in...
I have earlier presented a framework for hadronic rescattering Pythia in the context of pp collisions. In this talk, I will present the results from our recent paper where we have studied rescattering in pPb and PbPb collisions, using the Angantyr framework to generate heavy ion collisions. This will give a detailed view on how rescattering affects charged multiplicity and transverse momentum...
With the Run 2 and the upcoming high-luminosity phase at the LHC, improvements of theoretical predictions are crucial. In this talk I’ll be discussing the impact of EW corrections and approximations such as EW Sudakov logarithms using a generic and fully automated framework implemented in SHERPA. Another piece to consider in order to improve predictions is the loop induced through gluon...
Scattering amplitudes are often split up into their gauge (su(N)) and kinematic (two copies of complexified su(2)) components. Since the su(N) gauge part is often calculated using flows of colour, it should similarly be possible to describe the su(2) $\oplus$ su(2) kinematics of an amplitude in terms of flows of chirality. In two recent papers (hep-ph:2003.05877 & hep-ph:2011.10075) we showed...
In this work, we analyse the all-orders resummation structure of the momentum sharing fraction, $z_g$, opening angle, $\theta_g$, and relative transverse momentum, $k_{t,g}$, of the splitting tagged by the dynamical grooming procedure in hadronic collisions. We demonstrate that their resummation does non-exponentiate and it is free of clustering logarithms. Then, we analytically compute the...
Future lepton colliders, whether circular or linear, will provide unprecedented precision on standard model observables. The improvement to both the luminosity and detector techniques means that experimental error will be reduced by a factor 5-100 and therefore the theory uncertainties must also be reduced to the level of 0.001%. One of the major sources of theoretical uncertainties for lepton...
QCD parton showers can be improved by including different kinds of corrections. Among these are subleading color corrections, the modeling of QED emissions, and matrix element corrections. We implement a fixed color mode in the DIRE parton shower and combine it with QED shower emissions and mixed QCD-QED matrix element corrections to use these improvements simultaneously and compare their...
We present a "realistic" and in-depth analysis of how boosted top quark reconstruction techniques, e.g. using the HEPTopTagger toolkit, could be used to constrain the Wilson Coefficients (WCs) of top-sector BSM physics. The goal is to include the effects of jet-substructure mis-reconstruction on expected WC constraints and the effect of the on/off-shell nature of underlying top quark on the...
In this talk, we discuss a novel method to probing soft radiation beyond leading color with jet substructure, which measures the radiation pattern by looking at the difference between the direction point towards and away from the other jet of interest. In particular, we present some preliminary results for both color singlet and non-singlet configuration with the $e^{+}e^{-}\rightarrow$ three...
If dark mesons exist, their evolution and hadronization procedure are currently little constrained. They could decay promptly and result in a very SM QCD like jet structure, even though the original decaying particles are dark sector ones; they could behave as semi-visible jets; or they could behave as completely detector-stable hadrons, in which case the final state is just the missing...
