More Like this

1. New physics in single resonant top quarks

   https://doi.org/10.1007/JHEP02(2024)057  

   Tong, Shelley; Corcoran, James; Fieg, Max; Fenton, Michael; Whiteson, Daniel (February 2024, Journal of High Energy Physics)

   A<sc>bstract</sc> Searches for new physics in the top quark sector are of great theoretical interest, yet some powerful avenues for discovery remain unexplored. We characterize the expected statistical power of the LHC dataset to constrain the single production of heavy top partnersTdecaying to a top quark and a photon or a top quark and a gluon. We describe an effective interaction which could generate such production, though the limits apply to a range of theoretical models. We find sensitivity to cross sections in the 10²− 10⁵fb range, forTmasses between 300 and 1000 GeV, depending on decay mode. 

   more » « less
2. Reconstruction and identification of boosted di-τ systems in a search for Higgs boson pairs using 13 TeV proton-proton collision data in ATLAS

   https://doi.org/10.1007/JHEP11(2020)163  

   Aad, G.; Abbott, B.; Abbott, D. C.; Abed Abud, A.; Abeling, K.; Abhayasinghe, D. K.; Abidi, S. H.; AbouZeid, O. S.; Abraham, N. L.; Abramowicz, H.; et al (November 2020, Journal of High Energy Physics)

   null (Ed.)

   A bstract In this paper, a new technique for reconstructing and identifying hadronically decaying τ + τ − pairs with a large Lorentz boost, referred to as the di- τ tagger, is developed and used for the first time in the ATLAS experiment at the Large Hadron Collider. A benchmark di- τ tagging selection is employed in the search for resonant Higgs boson pair production, where one Higgs boson decays into a boosted $$ b\overline{b} $$ b b ¯ pair and the other into a boosted τ + τ − pair, with two hadronically decaying τ -leptons in the final state. Using 139 fb − 1 of proton-proton collision data recorded at a centre-of-mass energy of 13 TeV, the efficiency of the di- τ tagger is determined and the background with quark- or gluon-initiated jets misidentified as di- τ objects is estimated. The search for a heavy, narrow, scalar resonance produced via gluon-gluon fusion and decaying into two Higgs bosons is carried out in the mass range 1–3 TeV using the same dataset. No deviations from the Standard Model predictions are observed, and 95% confidence-level exclusion limits are set on this model. 

   more » « less
3. Measurement of beauty production via non-prompt D0 mesons in Pb-Pb collisions at $$ \sqrt{{\textrm{s}}_{\textrm{NN}}} $$ = 5.02 TeV

   https://doi.org/10.1007/JHEP12(2022)126  

   Acharya, S.; Adamová, D.; Adler, A.; Adolfsson, J.; Aglieri Rinella, G.; Agnello, M.; Agrawal, N.; Ahammed, Z.; Ahmad, S.; Ahn, S. U.; et al (December 2022, Journal of High Energy Physics)

   A bstract The production of non-prompt D 0 mesons from beauty-hadron decays was measured at midrapidity (| y | < 0 . 5) in Pb-Pb collisions at a nucleon-nucleon center-of-mass energy of $$ \sqrt{{\textrm{s}}_{\textrm{NN}}} $$ s NN = 5 . 02 TeV with the ALICE experiment at the LHC. Their nuclear modification factor ( R AA ), measured for the first time down to p T = 1 GeV /c in the 0–10% and 30–50% centrality classes, indicates a significant suppression, up to a factor of about three, for p T > 5 GeV /c in the 0–10% central Pb-Pb collisions. The data are described by models that include both collisional and radiative processes in the calculation of beauty-quark energy loss in the quark-gluon plasma, and quark recombination in addition to fragmentation as a hadronisation mechanism. The ratio of the non-prompt to prompt D 0 -meson R AA is larger than unity for p T > 4 GeV /c in the 0–10% central Pb-Pb collisions, as predicted by models in which beauty quarks lose less energy than charm quarks in the quark-gluon plasma because of their larger mass. 

   more » « less
4. Local, regional, and global adaptations to a compound pandemic-weather stress event

   https://doi.org/10.1088/1748-9326/acbbe3  

   Haqiqi, Iman; Grogan, Danielle S.; Bahalou Horeh, Marziyeh; Liu, Jing; Baldos, Uris L. C.; Lammers, Richard; Hertel, Thomas W. (February 2023, Environmental Research Letters)

   Abstract Global food security can be threatened by short-term extreme events that negatively impact food production, food purchasing power, and agricultural economic activity. At the same time, environmental pollutants like greenhouse gases (GHGs) can be reduced due to the same short-term extreme stressors. Stress events include pandemics like COVID-19 and widespread droughts like those experienced in 2015. Here we consider the question: what if COVID-19 had co-occurred with a 2015-like drought year? Using a coupled biophysical-economic modeling framework, we evaluate how this compound stress would alter both agricultural sector GHG emissions and change the number of undernourished people worldwide. We further consider three interdependent adaptation options: local water use for crop production, regional shifts in cropland area, and global trade of agricultural products. We find that GHG emissions decline due to reduced economic activity in the agricultural sector, but this is paired with large increases in undernourished populations in developing nations. Local and regional adaptations that make use of natural resources enable global-scale reductions in impacted populations via increased global trade. 

   more » « less
5. Search for dark QCD with emerging jets in proton-proton collisions at $$ \sqrt{s} $$ = 13 TeV

   https://doi.org/10.1007/JHEP07(2024)142  

   Hayrapetyan, A; Tumasyan, A; Adam, W; Andrejkovic, J W; Bergauer, T; Chatterjee, S; Damanakis, K; Dragicevic, M; Hussain, P S; Jeitler, M; et al (July 2024, Journal of High Energy Physics)

   A<sc>bstract</sc> A search for “emerging jets” produced in proton-proton collisions at a center-of-mass energy of 13 TeV is performed using data collected by the CMS experiment corresponding to an integrated luminosity of 138 fb⁻¹. This search examines a hypothetical dark quantum chromodynamics (QCD) sector that couples to the standard model (SM) through a scalar mediator. The scalar mediator decays into an SM quark and a dark sector quark. As the dark sector quark showers and hadronizes, it produces long-lived dark mesons that subsequently decay into SM particles, resulting in a jet, known as an emerging jet, with multiple displaced vertices. This search looks for pair production of the scalar mediator at the LHC, which yields events with two SM jets and two emerging jets at leading order. The results are interpreted using two dark sector models with different flavor structures, and exclude mediator masses up to 1950 (1950) GeV for an unflavored (flavor-aligned) dark QCD model. The unflavored results surpass a previous search for emerging jets by setting the most stringent mediator mass exclusion limits to date, while the flavor-aligned results provide the first direct mediator mass exclusion limits to date. 

   more » « less