scholarly journals $$ t\overline{t}t\overline{t} $$ signatures through the lens of color-octet scalars

2022 ◽  
Vol 2022 (1) ◽  
Author(s):  
Linda M. Carpenter ◽  
Taylor Murphy ◽  
Matthew J. Smylie

Abstract We reinterpret two recent LHC searches for events containing four top quarks $$ \left(t\overline{t}t\overline{t}\right) $$ t t ¯ t t ¯ in the context of supersymmetric models with Dirac gauginos and color-octet scalars (sgluons). We explore whether sgluon contributions to the four-top production cross section $$ \sigma \left( pp\to t\overline{t}t\overline{t}\right) $$ σ pp → t t ¯ t t ¯ can accommodate an excess of four-top events recently reported by the ATLAS collaboration. We also study constraints on these models from an ATLAS search for new phenomena with high jet multiplicity and significant missing transverse energy $$ \left({E}_{\mathrm{T}}^{\mathrm{miss}}\right) $$ E T miss sensitive to signals with four top quarks. We find that these two analyses provide complementary constraints, with the jets + $$ {E}_{\mathrm{T}}^{\mathrm{miss}} $$ E T miss search exceeding the four-top cross section measurement in sensitivity for sgluons heavier than about 800 GeV. We ultimately find that either a scalar or a pseudoscalar sgluon can currently fit the ATLAS excess in a range of reasonable benchmark scenarios, though a pseudoscalar in minimal Dirac gaugino models is ruled out. We finally offer sensitivity projections for these analyses at the HL-LHC, mapping the 5σ discovery potential in sgluon parameter space and computing exclusion limits at 95% CL in scenarios where no excess is found.

2005 ◽  
Vol 20 (14) ◽  
pp. 3174-3176
Author(s):  
◽  
REDA TAFIROUT

We report a measurement of the [Formula: see text] production cross section using dilepton events with jets and missing transverse energy in [Formula: see text] collisions at [Formula: see text]. Using 197 pb-1 of data recorded by the upgraded Collider Detector at Fermilab (CDF II), we use two complementary techniques to select candidate events. The combined result yields a [Formula: see text] production cross section of [Formula: see text] which is consistent with the Standard Model.


2020 ◽  
Vol 239 ◽  
pp. 01037
Author(s):  
X. Sun ◽  
H. Wang ◽  
H. Otsu ◽  
H. Sakurai ◽  
D.S. Ahn ◽  
...  

The isotopic production cross sections for the reactions of 136Xe induced by proton, deuteron and carbon at 168 MeV/u were obtained by using the inverse kinematics technique at RIKEN Radioactive Isotope Beam Factory. The target dependence of the cross sections was investigated systematically. It was found that for the light-mass products, the cross sections on carbon are larger than those on deuteron and proton. The measured cross sections on proton were compared with the previous data at higher reaction energies to study the energy dependence. The experimental results were compared with the theoretical calculations including both the intranuclear cascade and evaporation processes using PHITS and with the EPAX and SPACS empirical parameterizations.


2006 ◽  
Vol 21 (17) ◽  
pp. 1339-1353
Author(s):  
REINHARD SCHWIENHORST

We present a review of searches for electroweak production of single top quarks at the Fermilab Tevatron proton–antiproton collider at [Formula: see text]. Searches for s-channel and t-channel single top quark production have been carried out using secondary-vertex b-quark tagging and advanced event analysis methods in order to maximize the sensitivity to single top quark production. So far, no evidence for a single top quark signal has been found. However, 95% confidence level upper limits on the production cross-section have been set that improve upon previous limits by factors of two to three and are approaching the cross-section region predicted by the standard model.


2008 ◽  
Vol 665 (1) ◽  
pp. 1-8 ◽  
Author(s):  
V.M. Abazov ◽  
B. Abbott ◽  
M. Abolins ◽  
B.S. Acharya ◽  
M. Adams ◽  
...  

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