A search for electroweak $t\bar{t}Wj$ production in multileptonic final states at $\sqrt{s} = 13$ TeV with the ATLAS detector and bounds on effective field theory operators
Bibliographic record
Abstract
A search is presented for the electroweak production of a top-quark pair in association with a <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"> <a:mi>W</a:mi> </a:math> boson and at least one additional jet known as the <c:math xmlns:c="http://www.w3.org/1998/Math/MathML" display="inline"> <c:mi>t</c:mi> <c:mover accent="true"> <c:mi>t</c:mi> <c:mo stretchy="false">¯</c:mo> </c:mover> <c:mi>W</c:mi> <c:msub> <c:mi>j</c:mi> <c:mi>EW</c:mi> </c:msub> </c:math> process. This process has embedded within it a <g:math xmlns:g="http://www.w3.org/1998/Math/MathML" display="inline"> <g:mi>t</g:mi> <g:mi>W</g:mi> </g:math> -scattering vertex, which is probed directly for the first time. The collision data were collected with the ATLAS detector during Run 2 of the LHC and correspond to an integrated luminosity of <i:math xmlns:i="http://www.w3.org/1998/Math/MathML" display="inline"> <i:mn>140</i:mn> <i:mtext> </i:mtext> <i:mtext> </i:mtext> <i:msup> <i:mi>fb</i:mi> <i:mrow> <i:mo>−</i:mo> <i:mn>1</i:mn> </i:mrow> </i:msup> </i:math> at <k:math xmlns:k="http://www.w3.org/1998/Math/MathML" display="inline"> <k:msqrt> <k:mi>s</k:mi> </k:msqrt> <k:mo>=</k:mo> <k:mn>13</k:mn> <k:mtext> </k:mtext> <k:mtext> </k:mtext> <k:mi>TeV</k:mi> </k:math> . The search uses same-charge pairs of electrons and muons together with jets, of which at least one is <m:math xmlns:m="http://www.w3.org/1998/Math/MathML" display="inline"> <m:mi>b</m:mi> </m:math> -tagged. The properties of the most forward jet relative to the rest of the event are used to discriminate the electroweak <o:math xmlns:o="http://www.w3.org/1998/Math/MathML" display="inline"> <o:mi>t</o:mi> <o:mover accent="true"> <o:mi>t</o:mi> <o:mo stretchy="false">¯</o:mo> </o:mover> <o:mi>W</o:mi> <o:msub> <o:mi>j</o:mi> <o:mi>EW</o:mi> </o:msub> </o:math> production process from its strong <s:math xmlns:s="http://www.w3.org/1998/Math/MathML" display="inline"> <s:mi>t</s:mi> <s:mover accent="true"> <s:mi>t</s:mi> <s:mo stretchy="false">¯</s:mo> </s:mover> <s:mi>W</s:mi> </s:math> production counterpart. A measured (expected) 95% CL upper limit on the cross section is set at <w:math xmlns:w="http://www.w3.org/1998/Math/MathML" display="inline"> <w:msub> <w:mi>σ</w:mi> <w:mrow> <w:mi>t</w:mi> <w:mover accent="true"> <w:mi>t</w:mi> <w:mo stretchy="false">¯</w:mo> </w:mover> <w:mi>W</w:mi> <w:msub> <w:mi>j</w:mi> <w:mi>EW</w:mi> </w:msub> </w:mrow> </w:msub> <w:mo><</w:mo> <w:mn>251</w:mn> <w:mtext> </w:mtext> <w:mtext> </w:mtext> <w:mi>fb</w:mi> </w:math> (230 fb), to be compared with the expected Standard Model (SM) cross section of 47.7 fb. Limits are set on the SM effective field theory (EFT) operators <ab:math xmlns:ab="http://www.w3.org/1998/Math/MathML" display="inline"> <ab:msub> <ab:mi>O</ab:mi> <ab:mrow> <ab:mi>H</ab:mi> <ab:mi>t</ab:mi> </ab:mrow> </ab:msub> </ab:math> and <cb:math xmlns:cb="http://www.w3.org/1998/Math/MathML" display="inline"> <cb:msubsup> <cb:mi>O</cb:mi> <cb:mrow> <cb:mi>H</cb:mi> <cb:mi>Q</cb:mi> </cb:mrow> <cb:mrow> <cb:mo stretchy="false">(</cb:mo> <cb:mn>1</cb:mn> <cb:mo stretchy="false">)</cb:mo> </cb:mrow> </cb:msubsup> </cb:math> , which modify the electroweak couplings of the top quark through contributions to the <gb:math xmlns:gb="http://www.w3.org/1998/Math/MathML" display="inline"> <gb:mi>t</gb:mi> <gb:mi>W</gb:mi> </gb:math> -scattering vertex. The interpretation acts as a case study to emphasize the importance of energy-dependent sensitivity, multiprocess, and multioperator EFT contributions.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".