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The exotic particles that could finally break the standard model

‘Penguin’ decays from CERN’s latest Large Hadron Collider experiment hint at weird new physics.

Physicists think they've solved the muon mystery

Results dash hopes for a fifth force but provide very precise proof of Standard Model and QFT.

Search for new physics in triple boson production in proton-proton collisions at $\sqrt{s}$ = 13 TeV using the effective field theory approach

A search for new physics in the production of three massive gauge bosons (VVV, where V is a W or Z boson) is presented. The event selection is most effective in the Lorentz-boosted regime in which all three bosons have a transverse momentum ($p_\mathrm{T}$) above 200 GeV. Standard model (SM) processes contribute few events in this regime. When a boosted W or Z boson decays hadronically, the decay products tend to form a large-radius jet with substructure that reflects the presence of two quarks from the decay; such jets are called V-tagged jets. Special techniques to reconstruct and select V-tagged jets are applied. Events are categorized according to the number and kinematic features of charged leptons and V-tagged jets. Event yields are obtained in bins of a suitable kinematic variable such as the scalar $p_\mathrm{T}$ sum of the reconstructed objects in the event. No excess over SM expectations is observed. Bounds are placed on Wilson coefficients for a set of mass dimension-6 and -8 operators in the framework of SM effective field theory. The two most stringent bounds placed by this analysis are $-$0.13 $\lt$ $c_\mathrm{W}/Λ^2$ $\lt$ 0.12 TeV$^{-2}$ and $-$0.24 $\lt$ $c_\mathrm{Hq3}/Λ^2$ $\lt$ 0.21 TeV$^{-2}$ at 95% CL, where $c_\mathrm{W}$ and $c_\mathrm{Hq3}$ are dimension-6 Wilson coefficients in the Warsaw basis and $Λ$ is the mass scale of new physics.

First measurements of vector boson scattering in W$^\pm$W$^{\pm}$ and WZ production in all-leptonic final states at $\sqrt{s}$ = 13.6 TeV

The production cross sections of W$^\pm$W$^{\pm}$ and WZ boson pairs in association with two jets in proton-proton collisions are measured at $\sqrt{s}$ = 13.6 TeV. The data sample corresponds to an integrated luminosity of 171 fb$^{-1}$, collected with the CMS detector during 2022$-$2024. The measurements are performed in the leptonic decay modes: W$^{\pm}$Z $\to$ $\ell^\pmν\ell^{\prime\pm}\ell^{\prime\mp}$ and W$^\pm$W$^{\pm}$ $\to$ $\ell^\pmν\ell^{\prime\pm}ν$, where $\ell, \ell'$ = e or $μ$. The electroweak productions of W$^\pm$W$^{\pm}$ and WZ bosons are each observed with a significance greater than five standard deviations from the background-only hypothesis. Differential fiducial cross sections as functions of several observables are also measured.

A strange ‘neutrino force’ helped heal a crack in particle physics

A neglected force produced by neutrinos and other particles helps atomic physics measurements align with predictions of the standard model.

First measurements of vector boson scattering in $ \mathrm{W}^{\pm}\mathrm{W}^{\pm} $ and $ \mathrm{W}\mathrm{Z} $ production in all-leptonic final states at $ \sqrt{s} = $ 13.6 TeV

The production cross sections of $ \mathrm{W}^{\pm}\mathrm{W}^{\pm} $ and WZ boson pairs in association with two jets in proton-proton collisions are measured at $ \sqrt{s}= $ 13.6 TeV. The data sample corresponds to an integrated luminosity of 171 fb$ ^{-1} $, collected with the CMS detector during 2022--2024. The measurements are performed in the leptonic decay modes: $ \mathrm{W}^{\pm}\mathrm{Z} \to \ell^{\pm}\nu{\ell^{\prime\pm}}{\ell^{\prime\mp}} $ and $ \mathrm{W}^{\pm}\mathrm{W}^{\pm} \to \ell^\pm\nu {\ell}^{\prime\pm}\nu $, where $ \ell, {\ell}{\prime} = \mathrm{e} $ or $ \mu $. The electroweak productions of $ \mathrm{W}^{\pm}\mathrm{W}^{\pm} $ and WZ bosons are each observed with a significance greater than five standard deviations from the background-only hypothesis. Differential fiducial cross sections as functions of several observables are also measured.

Search for new physics in triple boson production in proton-proton collisions at $ \sqrt{s} = $ 13 TeV using the effective field theory approach

A search for new physics in the production of three massive gauge bosons ($ \mathrm{V}\mathrm{V}\mathrm{V} $, where V is a W or Z boson) is presented. The event selection is most effective in the Lorentz-boosted regime in which all three bosons have a transverse momentum ($ p_{\mathrm{T}} $) above 200 GeV. Standard model (SM) processes contribute few events in this regime. When a boosted W or Z boson decays hadronically, the decay products tend to form a large-radius jet with substructure that reflects the presence of two quarks from the decay; such jets are called V-tagged jets. Special techniques to reconstruct and select V-tagged jets are applied. Events are categorized according to the number and kinematic features of charged leptons and V-tagged jets. Event yields are obtained in bins of a suitable kinematic variable such as the scalar $ p_{\mathrm{T}} $ sum of the reconstructed objects in the event. No excess over SM expectations is observed. Bounds are placed on Wilson coefficients for a set of mass dimension-6 and -8 operators in the framework of SM effective field theory. The two most stringent bounds placed by this analysis are $ -0.13 < c_\mathrm{W}/\Lambda^2 < 0.12 \text{TeV}^{-2} $ and $ -0.24 < c_{\text{Hq3}}/\Lambda^2 < 0.21 \text{TeV}^{-2} $ at 95\% CL, where $ c_\mathrm{W} $ and $ c_{\text{Hq3}} $ are dimension-6 Wilson coefficients in the Warsaw basis and $ \Lambda $ is the mass scale of new physics.