A data-driven method for Higgs boson analyses in di-τ final states for the LHC Run II and beyond

Das τ-Embedding ist eine datenbasierte Methode zur Abschätzung des Beitrags von Prozessen mit zwei τ-Leptonen im Ereignis. Die Methode verwendet einen ereignisbasier- ten Ansatz, bei dem zwei rekonstruierte Myonen in den Daten ausgewählt werden, die durch zwei simulierte τ-Leptonenzerfälle ersetzt werden. Das daraus resultierende Ereignis vereint die simulierten τ-Leptonenzerfälle mit einem sonst unveränderten Ereignis. Das τ-Embedding führt zu einer verbesserten Beschreibung der Eigenschaften von Jets und von Pile-up-Kollisionen. Es ist die wichtigste Abschätzungsmethode für Untergründe mit zwei τ-Leptonen im Endzustand innerhalb der CMS-Kollaboration und wurde in den letzten Jahren in zahlreichen Higgs-Boson-Analysen in ττ-Endzuständen angewendet. In dieser Arbeit wird die neueste Implementierung der Methode beschrieben. In einem umfassenden, Analysebeispiel wird die Methode mit einem Modell verglichen, das auf vollständig simulierten Prozessen basiert. Mehr als 8 Millionen CPU-Stunden wurden auf- gewendet, um die neue Implementierung von τ-Embedding Ergebnisse für die LHC Run II Analysen zu erzeugen. Die vorgestellten Studien legen den Grundstein für die Verwendung von τ-Embedding in mehreren geplanten Higgs-Boson-Analysen in ττ-Endzuständen auf den kombinierten Datensätzen von Run II und III, die eines der wichtigsten Ergebnisse des LHC-Phase-1-Physikprogramms darstellen werden

Performance of the bwHPC cluster in the production of μ -> t embedded events used for the prediction of background for H -> tt analyses

In high energy physics, a main challenge is the accurate prediction of background events at a particle detector. These events are usually estimated by simulation. As an alternative, data-driven methods use observed events to derive a background prediction and are often less computationally expensive than simulation. The lepton embedding method presents a data-driven method to estimate the background from Z ! events for Higgs boson analyses in the same final state. Z ! μμ events recorded by the CMS experiment are selected, the muons are removed from the event and replaced with simulated leptons with the same kinematic properties as the removed muons. The resulting hybrid event provides an improved description of pile-up and the underlying event compared to the simulation of the full proton-proton collision. In this paper the production of these hybrid events used by the CMS collaboration is described. The production relies on the resources made available by the bwHPC project. The data used for this purpose correspond to 65 million di-muon events collected in 2017 by CMS

Search for new particles in events with energetic jets and large missing transverse momentum in proton-proton collisions at root s=13 TeV

A search is presented for new particles produced at the LHC in proton-proton collisions at root s = 13 TeV, using events with energetic jets and large missing transverse momentum. The analysis is based on a data sample corresponding to an integrated luminosity of 101 fb(-1), collected in 2017-2018 with the CMS detector. Machine learning techniques are used to define separate categories for events with narrow jets from initial-state radiation and events with large-radius jets consistent with a hadronic decay of a W or Z boson. A statistical combination is made with an earlier search based on a data sample of 36 fb(-1), collected in 2016. No significant excess of events is observed with respect to the standard model background expectation determined from control samples in data. The results are interpreted in terms of limits on the branching fraction of an invisible decay of the Higgs boson, as well as constraints on simplified models of dark matter, on first-generation scalar leptoquarks decaying to quarks and neutrinos, and on models with large extra dimensions. Several of the new limits, specifically for spin-1 dark matter mediators, pseudoscalar mediators, colored mediators, and leptoquarks, are the most restrictive to date.Peer reviewe

Probing effective field theory operators in the associated production of top quarks with a Z boson in multilepton final states at root s=13 TeV

Peer reviewe

An embedding technique to determine ττ backgrounds in proton-proton collision data

An embedding technique is presented to estimate standard model tau tau backgrounds from data with minimal simulation input. In the data, the muons are removed from reconstructed mu mu events and replaced with simulated tau leptons with the same kinematic properties. In this way, a set of hybrid events is obtained that does not rely on simulation except for the decay of the tau leptons. The challenges in describing the underlying event or the production of associated jets in the simulation are avoided. The technique described in this paper was developed for CMS. Its validation and the inherent uncertainties are also discussed. The demonstration of the performance of the technique is based on a sample of proton-proton collisions collected by CMS in 2017 at root s = 13 TeV corresponding to an integrated luminosity of 41.5 fb(-1).Peer reviewe

riga/law: v0.1.15

<h2>Breaking changes</h2> <p><em>None</em></p> <h2>Features & improvements</h2> <ul> <li>Split image workflows. (65e6b32)</li> <li>Streamline docker image builds, add alma9 images. (#169) (e4afe3a)</li> <li>Add custom parameter base class. (e16012b)</li> <li>Preserve job data of skipped jobs. (57b5328)</li> </ul> <h2>Fixes</h2> <ul> <li>Fix parameter encoding for law_run(). (4a0372b)</li> <li>Fix localize decorator. (9c2df74)</li> <li>Update CmdlineParser patch. (6d39db0)</li> </ul> <h2><code>contrib</code> packages</h2> <ul> <li>[htcondor] Improve error extraction from query response. (4d843dd)</li> </ul&gt

Inclusive nonresonant multilepton probes of new phenomena at s\sqrt{s} = 13 TeV

An inclusive search for nonresonant signatures of beyond the standard model (SM) phenomena in events with three or more charged leptons, including hadronically decaying $\tau$ leptons, is presented. The analysis is based on a data sample corresponding to an integrated luminosity of 138 fb$^{-1}$ of proton-proton collisions at $\sqrt{s}$ = 13 TeV, collected by the CMS experiment at the LHC in 2016-2018. Events are categorized based on the lepton and b-tagged jet multiplicities and various kinematic variables. Three scenarios of physics beyond the SM are probed, and signal-specific boosted decision trees are used for enhancing sensitivity. No significant deviations from the background expectations are observed. Lower limits are set at 95% confidence level on the mass of type-III seesaw heavy fermions in the range 845-1065 GeV for various decay branching fraction combinations to SM leptons. Doublet and singlet vector-like $\tau$ lepton extensions of the SM are excluded for masses below 1045 GeV and in the mass range 125-150 GeV, respectively. Scalar leptoquarks decaying exclusively to a top quark and a lepton are excluded below 1.12-1.42 TeV, depending on the lepton flavor. For the type-III seesaw as well as the vector-like doublet model, these constraints are the most stringent to date. For the vector-like singlet model, these are the first constraints from the LHC experiments. Detailed results are also presented to facilitate alternative theoretical interpretations

Inclusive nonresonant multilepton probes of new phenomena at s\sqrt{s} = 13 TeV

An inclusive search for nonresonant signatures of beyond the standard model (SM) phenomena in events with three or more charged leptons, including hadronically decaying $\tau$ leptons, is presented. The analysis is based on a data sample corresponding to an integrated luminosity of 138 fb$^{-1}$ of proton-proton collisions at $\sqrt{s}$ = 13 TeV, collected by the CMS experiment at the LHC in 2016-2018. Events are categorized based on the lepton and b-tagged jet multiplicities and various kinematic variables. Three scenarios of physics beyond the SM are probed, and signal-specific boosted decision trees are used for enhancing sensitivity. No significant deviations from the background expectations are observed. Lower limits are set at 95% confidence level on the mass of type-III seesaw heavy fermions in the range 845-1065 GeV for various decay branching fraction combinations to SM leptons. Doublet and singlet vector-like $\tau$ lepton extensions of the SM are excluded for masses below 1045 GeV and in the mass range 125-150 GeV, respectively. Scalar leptoquarks decaying exclusively to a top quark and a lepton are excluded below 1.12-1.42 TeV, depending on the lepton flavor. For the type-III seesaw as well as the vector-like doublet model, these constraints are the most stringent to date. For the vector-like singlet model, these are the first constraints from the LHC experiments. Detailed results are also presented to facilitate alternative theoretical interpretations