This report of the BOOST2012 workshop presents the results of four working groups that studied key aspects of jet substructure. We discuss the potential of the description of jet substructure in ...first-principle QCD calculations and study the accuracy of state-of-the-art Monte Carlo tools. Experimental limitations of the ability to resolve substructure are evaluated, with a focus on the impact of additional proton proton collisions on jet substructure performance in future LHC operating scenarios. A final section summarizes the lessons learnt during the deployment of substructure analyses in searches for new physics in the production of boosted top quarks.
A stereoscopic system based on a multispectral camera and an LCD projector uses multispectral information for 3D object reconstruction. By linking 3D points to a curve representing the spectral ...reflectance, the system gives a physical representation of the matter that's independent from illuminant, observer, and acquisition devices
Soft drop Larkoski, Andrew J.; Marzani, Simone; Soyez, Gregory ...
The journal of high energy physics,
05/2014, Letnik:
2014, Številka:
5
Journal Article
Recenzirano
Odprti dostop
A
bstract
We introduce a new jet substructure technique called “soft drop declustering”, which recursively removes soft wide-angle radiation from a jet. The soft drop algorithm depends on two ...parameters — a soft threshold
z
cut
and an angular exponent
β
— with the
β
= 0 limit corresponding roughly to the (modified) mass drop procedure. To gain an analytic understanding of soft drop and highlight the
β
dependence, we perform resummed calculations for three observables on soft-dropped jets: the energy correlation functions, the groomed jet radius, and the energy loss due to soft drop. The
β
= 0 limit of the energy loss is particularly interesting, since it is not only “Sudakov safe” but also largely insensitive to the value of the strong coupling constant. While our calculations are strictly accurate only to modified leading-logarithmic order, we also include a discussion of higher-order effects such as multiple emissions and (the absence of) non-global logarithms. We compare our analytic results to parton shower simulations and find good agreement, and we also estimate the impact of non-perturbative effects such as hadronization and the underlying event. Finally, we demonstrate how soft drop can be used for tagging boosted
W
bosons, and we speculate on the potential advantages of using soft drop for pileup mitigation.
Soft-drop thrust Baron, Jeremy; Marzani, Simone; Theeuwes, Vincent
The journal of high energy physics,
08/2018, Letnik:
2018, Številka:
8
Journal Article
Recenzirano
Odprti dostop
A
bstract
Soft drop, a technique originally developed in the context of jet physics in proton-proton collisions in order to reduce the contamination from non-perturbative effects, is applied to event ...shapes in electron-positron annihilation. In particular, we study the thrust distribution at the
Z
pole and show that the region where non-perturbative corrections due to the hadronisation process are small is considerably extended if soft drop is applied. Therefore, we argue that the use of soft drop to reduce hadronisation effects is potentially of great benefit in the context of strong coupling determination using event shapes, which would be otherwise characterised by a strong correlation between
α
s
and non-perturbative parameters. However, reduced sensitivity to hadronisation corrections is only one of the aspects that need to be considered. In this context, we show that perturbative calculability, especially away from the soft and collinear region of the event-shape spectrum, has a nontrivial interplay with the soft-drop observable of choice. To this purpose, besides thrust, we investigate the behaviour of the hemisphere mass as well as the jet mass. We find that the latter shows the most promising behaviour in the intermediate region of the spectrum, especially if small jet radii are considered.
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