arXiv subjects

T. Mäkelä

Publications and source records attributed to T. Mäkelä.

3 recordsLinked to original sources

arXiv2026

Spin Identification of Dark Sector Mediators through Angular Distributions

A variety of experiments are operating or planned to search for displaced decays of light long-lived dark sector particles. In case such a state is discovered, the next step is determining its quantum numbers. We identify an angular observable, reconstructible solely from the decay products' four-momenta, that exhibits an anisotropic distribution for vector bosons from light meson decays and an isotropic distribution for scalars. We demonstrate that searches at DUNE, SHiP and FASER2 will be able to identify the mediator spin in sizable regions of yet unconstrained parameter space.

hep-ph↗

arXiv2022

xFitter: An Open Source QCD Analysis Framework. A resource and reference document for the Snowmass study

We provide an overview of the xFitter open-source software package, review the general capabilities of the program, and highlight applications relevant to the Snowmass study. An updated version of the program (2.2.0) is available on CERN GitLab, a and this has been updated to a C++ codebase with enhanced and extended features. We also discuss some of the ongoing and future code developments that may be useful for precision studies. We survey recent analyses performed by the xFitter developers' team including: W and Z production, photon PDFs, Drell-Yan forward-backward asymmetry studies, resummation of small-x contributions, heavy quark production, constraints on the strange PDF, determination of the pion PDF, and determination of the pion Fragmentation Functions. Finally, we briefly summarize selected applications of xFitter in the literature. The xFitter program is a versatile, flexible, modular, and comprehensive tool that can provide impact studies for possible future facilities. We encourage the use of xFitter, and welcome new contributions from the community.

hep-ph↗

arXiv2021

Top mass shift resulting from the recalibration of flavor-dependent jet energy corrections in the DØ lepton+jets top mass measurement

We review the possible effects of the miscalibration of the flavor-dependent Jet Energy Corrections ($F_{\mathrm{Corr}}$) on the DØ lepton+jets top mass measurement. The work is based on a previous study, where the DØ $F_{\mathrm{Corr}}$ calibration procedure was repeated based on the release of the internal DØ notes after a 5-year moratorium. The cited study was motivated by the extraordinary precision claimed by DØ in their top mass measurement. Using a Pythia6-based $F_{\mathrm{Corr}}$ recalibration, the $m_t$ result was shifted from 174.95 to 173.16 GeV. Moreover, utilizing a Herwig7-based $F_{\mathrm{Corr}}$ calibration (not accounted for in DØ studies), a shift down to 171.84 GeV was observed. We find this both convincing and specific evidence for re-reviewing a part of the $F_{\mathrm{Corr}}$ calibration process. However, DØ has been unwilling to open such studies or to provide other convincing counter-evidence.

hep-ex↗