Direct constraint on the Higgs–charm coupling from a search for Higgs boson decays into charm quarks with the ATLAS detector
Creators: name: Aad, G
name: Abbott, B
name: Abbott, DC
name: Abud, AA
name: Abeling, K
name: Abhayasinghe, DK
name: Abidi, SH
name: Aboulhorma, A
name: Abramowicz, H
name: Abreu, H
name: Abulaiti, Y
name: Hoffman, ACA
name: Acharya, BS
name: Achkar, B
name: Adam, L
name: Bourdarios, CA
name: Adamczyk, L
name: Adamek, L
name: Addepalli, SV
name: Adelman, J
name: Adiguzel, A
name: Adorni, S
name: Adye, T
name: Affolder, AA
name: Afik, Y
name: Agaras, MN
name: Agarwala, J
name: Aggarwal, A
name: Agheorghiesei, C
name: Aguilar-Saavedra, JA
name: Ahmad, A
name: Ahmadov, F
name: Ahmed, WS
name: Ai, X
name: Aielli, G
name: Aizenberg, I
name: Akbiyik, M
name: Åkesson, TPA
name: Akimov, AV
name: Khoury, KA
name: Alberghi, GL
name: Albert, J
name: Albicocco, P
name: Verzini, MJA
name: Alderweireldt, S
name: Aleksa, M
name: Aleksandrov, IN
name: Alexa, C
name: Alexopoulos, T
name: Alfonsi, A
name: Alfonsi, F
name: Alhroob, M
name: Ali, B
name: Ali, S
name: Aliev, M
name: Alimonti, G
name: Allaire, C
name: Allbrooke, BMM
name: Allport, PP
name: Aloisio, A
name: Alonso, F
name: Alpigiani, C
name: Camelia, EA
name: Estevez, MA
name: Alviggi, MG
name: Coutinho, YA
name: Ambler, A
name: Ambroz, L
name: Amelung, C
name: Amidei, D
name: Santos, SPAD
name: Amoroso, S
name: Amos, KR
name: Amrouche, CS
name: Ananiev, V
name: Anastopoulos, C
name: Andari, N
name: Andeen, T
name: Anders, JK
name: Andrean, SY
name: Andreazza, A
name: Angelidakis, S
name: Angerami, A
name: Anisenkov, AV
name: Annovi, A
name: Antel, C
name: Anthony, MT
name: Antipov, E
name: Antonelli, M
name: Antrim, DJA
name: Anulli, F
name: Aoki, M
name: Pozo, JAA
name: Aparo, MA
name: Bella, LA
name: Appelt, C
name: Aranzabal, N
name: Ferraz, VA
name: Arcangeletti, C
name: Arce, ATH
Publisher: name: Apollo - University of Cambridge Repository
Year: 2022
Subjects: Regular Article - Experimental Physics

description: A search for the Higgs boson decaying into a pair of charm quarks is presented. The analysis uses proton-proton collisions to target the production of a Higgs boson in association with a leptonically decaying $W$ or $Z$ boson. The dataset delivered by the LHC at a centre-of-mass energy of $\sqrt{s}=13$ TeV and recorded by the ATLAS detector corresponds to an integrated luminosity of 139 fb$^{-1}$. Flavour-tagging algorithms are used to identify jets originating from the hadronisation of charm quarks. The analysis method is validated with the simultaneous measurement of $WW,WZ$ and $ZZ$ production, with observed (expected) significances of $2.6$ ($2.2$) standard deviations above the background-only prediction for the $(W/Z)Z(\to c\bar{c})$ process and $3.8$ ($4.6$) standard deviations for the $(W/Z)W(\to cq)$ process. The $(W/Z)H(\to c \bar{c})$ search yields an observed (expected) upper limit of $26$ ($31$) times the predicted Standard Model cross-section times branching fraction for a Higgs boson with a mass of 125 GeV, corresponding to an observed (expected) constraint on the charm Yukawa coupling modifier $|\kappa_c| &lt; 8.5 (12.4)$, at the 95% confidence level. A combination with the ATLAS $(W/Z)H, H\to b\bar{b}$ analysis is performed, allowing the ratio $\kappa_c / \kappa_b$ to be constrained without assumptions about the width of the Higgs boson. The ratio is constrained to be $|\kappa_c / \kappa_b| &lt; 4.5$ at the 95% confidence level, smaller than the ratio of the $b$- and $c$-quark masses, and therefore determines the Higgs-charm coupling to be weaker than the Higgs-bottom coupling at the 95% confidence level.