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1. Charm production and fragmentation fractions at midrapidity in pp collisions at $$ \sqrt{\textrm{s}} $$ = 13 TeV

   https://doi.org/10.1007/JHEP12(2023)086  

   Acharya, S; Adamová, D; Aglieri_Rinella, G; Agnello, M; Agrawal, N; Ahammed, Z; Ahmad, S; Ahn, S U; Ahuja, I; Akindinov, A; et al (December 2023, Journal of High Energy Physics)

   A<sc>bstract</sc> Measurements of the production cross sections of prompt D⁰, D⁺, D^*+,$$ {\textrm{D}}_{\textrm{s}}^{+} $$ $D_s^{+}$,$$ {\Lambda}_{\textrm{c}}^{+} $$ ${\Lambda }_c^{+}$, and$$ {\Xi}_{\textrm{c}}^{+} $$ ${\Xi }_c^{+}$charm hadrons at midrapidity in proton-proton collisions at$$ \sqrt{s} $$ $\sqrt{s}$= 13 TeV with the ALICE detector are presented. The D-meson cross sections as a function of transverse momentum (p_T) are provided with improved precision and granularity. The ratios ofp_T-differential meson production cross sections based on this publication and on measurements at different rapidity and collision energy provide a constraint on gluon parton distribution functions at low values of Bjorken-x(10⁻⁵–10⁻⁴). The measurements of$$ {\Lambda}_{\textrm{c}}^{+} $$ ${\Lambda }_c^{+}$($$ {\Xi}_{\textrm{c}}^{+} $$ ${\Xi }_c^{+}$) baryon production extend the measuredp_Tintervals down top_T= 0(3) GeV/c. These measurements are used to determine the charm-quark fragmentation fractions and the$$ \textrm{c}\overline{\textrm{c}} $$ $c\overline{c}$production cross section at midrapidity (|y|<0.5) based on the sum of the cross sections of the weakly-decaying ground-state charm hadrons D⁰, D⁺,$$ {\textrm{D}}_{\textrm{s}}^{+} $$ $D_s^{+}$,$$ {\Lambda}_{\textrm{c}}^{+} $$ ${\Lambda }_c^{+}$,$$ {\Xi}_{\textrm{c}}^0 $$ ${\Xi }_c^0$and, for the first time,$$ {\Xi}_{\textrm{c}}^{+} $$ ${\Xi }_c^{+}$, and of the strongly-decaying J/ψmesons. The first measurements of$$ {\Xi}_{\textrm{c}}^{+} $$ ${\Xi }_c^{+}$and$$ {\Sigma}_{\textrm{c}}^{0,++} $$ ${\Sigma }_c^{0,++}$fragmentation fractions at midrapidity are also reported. A significantly larger fraction of charm quarks hadronising to baryons is found compared to e⁺e⁻and ep collisions. The$$ \textrm{c}\overline{\textrm{c}} $$ $c\overline{c}$production cross section at midrapidity is found to be at the upper bound of state-of-the-art perturbative QCD calculations. 

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2. Measurement of beauty production via non-prompt charm hadrons in p–Pb collisions at $$ \sqrt{s_{\textrm{NN}}} $$ = 5.02 TeV

   https://doi.org/10.1007/JHEP11(2024)148  

   Acharya, S; Adamová, D; Agarwal, A; Aglieri_Rinella, G; Aglietta, L; Agnello, M; Agrawal, N; Ahammed, Z; Ahmad, S; Ahn, S U; et al (November 2024, Journal of High Energy Physics)

   A<sc>bstract</sc> The production cross sections of D⁰, D⁺, and$$ {\Lambda}_{\textrm{c}}^{+} $$ ${\Lambda }_c^{+}$hadrons originating from beauty-hadron decays (i.e. non-prompt) were measured for the first time at midrapidity in proton–lead (p–Pb) collisions at the center-of-mass energy per nucleon pair of$$ \sqrt{s_{\textrm{NN}}} $$ $\sqrt{s_{\mathrm{NN}}}$= 5.02 TeV. Nuclear modification factors (R_pPb) of non-prompt D⁰, D⁺, and$$ {\Lambda}_{\textrm{c}}^{+} $$ ${\Lambda }_c^{+}$are calculated as a function of the transverse momentum (p_T) to investigate the modification of the momentum spectra measured in p–Pb collisions with respect to those measured in proton–proton (pp) collisions at the same energy. TheR_pPbmeasurements are compatible with unity and with the measurements in the prompt charm sector, and do not show a significantp_Tdependence. Thep_T-integrated cross sections andp_T-integratedR_pPbof non-prompt D⁰and D⁺mesons are also computed by extrapolating the visible cross sections down top_T= 0. The non-prompt D-mesonR_pPbintegrated overp_Tis compatible with unity and with model calculations implementing modification of the parton distribution functions of nucleons bound in nuclei with respect to free nucleons. The non-prompt$$ {\Lambda}_{\textrm{c}}^{+} $$ ${\Lambda }_c^{+}$/D⁰and D⁺/D⁰production ratios are computed to investigate hadronisation mechanisms of beauty quarks into mesons and baryons. The measured ratios as a function ofp_Tdisplay a similar trend to that measured for charm hadrons in the same collision system. 

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3. Measurement of inclusive charged-particle jet production in pp and p-Pb collisions at $$ \sqrt{s_{\textrm{NN}}} $$ = 5.02 TeV

   https://doi.org/10.1007/JHEP05(2024)041  

   Acharya, S; Adamová, D; Adler, A; Aglieri_Rinella, G; Agnello, M; Agrawal, N; Ahammed, Z; Ahmad, S; Ahn, S U; Ahuja, I; et al (May 2024, Journal of High Energy Physics)

   A<sc>bstract</sc> Measurements of inclusive charged-particle jet production in pp and p-Pb collisions at center-of-mass energy per nucleon-nucleon collision$$ \sqrt{s_{\textrm{NN}}} $$ $\sqrt{s_{\mathrm{NN}}}$= 5.02 TeV and the corresponding nuclear modification factor$$ {R}_{\textrm{pPb}}^{\textrm{ch}\ \textrm{jet}} $$ $R_{\mathrm{pPb}}^{\mathrm{ch}\mathrm{jet}}$are presented, using data collected with the ALICE detector at the LHC. Jets are reconstructed in the central rapidity region |η_jet|<0.5 from charged particles using the anti-k_Talgorithm with resolution parametersR= 0.2, 0.3, and 0.4. Thep_T-differential inclusive production cross section of charged-particle jets, as well as the corresponding cross section ratios, are reported for pp and p-Pb collisions in the transverse momentum range 10<$$ {p}_{\textrm{T},\textrm{jet}}^{\textrm{ch}} $$ $p_{T,\mathrm{jet}}^{\mathrm{ch}}$<140 GeV/cand 10<$$ {p}_{\textrm{T},\textrm{jet}}^{\textrm{ch}} $$ $p_{T,\mathrm{jet}}^{\mathrm{ch}}$<160 GeV/c, respectively, together with the nuclear modification factor$$ {R}_{\textrm{pPb}}^{\textrm{ch}\ \textrm{jet}} $$ $R_{\mathrm{pPb}}^{\mathrm{ch}\mathrm{jet}}$in the range 10<$$ {p}_{\textrm{T},\textrm{jet}}^{\textrm{ch}} $$ $p_{T,\mathrm{jet}}^{\mathrm{ch}}$<140 GeV/c. The analysis extends thep_Trange of the previously-reported charged-particle jet measurements by the ALICE Collaboration. The nuclear modification factor is found to be consistent with one and independent of the jet resolution parameter with the improved precision of this study, indicating that the possible influence of cold nuclear matter effects on the production cross section of charged-particle jets in p-Pb collisions at$$ \sqrt{s_{\textrm{NN}}} $$ $\sqrt{s_{\mathrm{NN}}}$= 5.02 TeV is smaller than the current precision. The obtained results are in agreement with other minimum bias jet measurements available for RHIC and LHC energies, and are well reproduced by the NLO perturbative QCD Powhegcalculations with parton shower provided by Pythia8 as well as by Jetscapesimulations. 

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4. Search for a high-mass dimuon resonance produced in association with b quark jets at $$ \sqrt{s} $$ = 13 TeV

   https://doi.org/10.1007/JHEP10(2023)043  

   Hayrapetyan, A.; Tumasyan, A.; Adam, W.; Andrejkovic, J. W.; Bergauer, T.; Chatterjee, S.; Damanakis, K.; Dragicevic, M.; Escalante Del Valle, A.; Hussain, P. S.; et al (October 2023, Journal of High Energy Physics)

   A<sc>bstract</sc> A search for high-mass dimuon resonance production in association with one or more b quark jets is presented. The study uses proton-proton collision data collected with the CMS detector at the LHC corresponding to an integrated luminosity of 138 fb⁻¹at a center-of-mass energy of 13 TeV. Model-independent limits are derived on the number of signal events with exactly one or more than one b quark jet. Results are also interpreted in a lepton-flavor-universal model with Z′ boson couplings to a bb quark pair (g_b), an sb quark pair (g_bδ_bs), and any same-flavor charged lepton (g_ℓ) or neutrino pair (g_ν), with|g_ν|=|g_ℓ|. For a Z′ boson with a mass$$ {m}_{{\textrm{Z}}^{\prime }} $$ $m_{Z^{\prime }}$= 350 GeV (2 TeV) and|δ_bs|< 0.25, the majority of the parameter space with 0.0057 <|g_ℓ|< 0.35 (0.25 <|g_ℓ|< 0.43) and 0.0079 < |g_b| < 0.46 (0.34 < |g_b| < 0.57) is excluded at 95% confidence level. Finally, constraints are set on a Z′ model with parameters consistent with low-energy b → sℓℓmeasurements. In this scenario, most of the allowed parameter space is excluded for a Z′ boson with 350 <$$ {m}_{{\textrm{Z}}^{\prime }} $$ $m_{Z^{\prime }}$< 500 GeV, while the constraints are less stringent for higher$$ {m}_{{\textrm{Z}}^{\prime }} $$ $m_{Z^{\prime }}$hypotheses. This is the first dedicated search at the LHC for a high-mass dimuon resonance produced in association with multiple b quark jets, and the constraints obtained on models with this signature are the most stringent to date. 

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5. Differential cross-section measurements of Higgs boson production in the H → τ+τ− decay channel in pp collisions at $$ \sqrt{s} $$ = 13 TeV with the ATLAS detector

   https://doi.org/10.1007/JHEP03(2025)010  

   Aad, G; Aakvaag, E; Abbott, B; Abdelhameed, S; Abeling, K; Abicht, N J; Abidi, S H; Aboelela, M; Aboulhorma, A; Abramowicz, H; et al (March 2025, Journal of High Energy Physics)

   A<sc>bstract</sc> Differential measurements of Higgs boson production in theτ-lepton-pair decay channel are presented in the gluon fusion, vector-boson fusion (VBF),VHand$$ t\overline{t}H $$ $t\overline{t}H$associated production modes, with particular focus on the VBF production mode. The data used to perform the measurements correspond to 140 fb⁻¹of proton-proton collisions collected by the ATLAS experiment at the LHC. Two methods are used to perform the measurements: theSimplified Template Cross-Section(STXS) approach and anUnfolded Fiducial Differentialmeasurement considering only the VBF phase space. For the STXS measurement, events are categorized by their production mode and kinematic properties such as the Higgs boson’s transverse momentum ($$ {p}_{\textrm{T}}^{\textrm{H}} $$ $p_T^H$), the number of jets produced in association with the Higgs boson, or the invariant mass of the two leading jets (m_jj). For the VBF production mode, the ratio of the measured cross-section to the Standard Model prediction form_jj> 1.5 TeV and$$ {p}_{\textrm{T}}^{\textrm{H}} $$ $p_T^H$> 200 GeV ($$ {p}_{\textrm{T}}^{\textrm{H}} $$ $p_T^H$< 200 GeV) is$$ {1.29}_{-0.34}^{+0.39} $$ ${1.29}_{-0.34}^{+0.39}$($$ {0.12}_{-0.33}^{+0.34} $$ ${0.12}_{-0.33}^{+0.34}$). This is the first VBF measurement for the higher-$$ {p}_{\textrm{T}}^{\textrm{H}} $$ $p_T^H$criteria, and the most precise for the lower-$$ {p}_{\textrm{T}}^{\textrm{H}} $$ $p_T^H$criteria. Thefiducialcross-section measurements, which only consider the kinematic properties of the event, are performed as functions of variables characterizing the VBF topology, such as the signed ∆ϕ_jjbetween the two leading jets. The measurements have a precision of 30%–50% and agree well with the Standard Model predictions. These results are interpreted in the SMEFT framework, and place the strongest constraints to date on the CP-odd Wilson coefficient$$ {c}_{H\overset{\sim }{W}} $$ $c_{H\tilde{W}}$. 

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