Proton Size Shrunk: Long-Standing Physics Discrepancy Potentially Resolved
German scientists used a super-precise laser to measure the proton's size. This could solve a 16-year-old physics mystery about its radius.
#ProtonRadius, #PhysicsNews, #StandardModel, #QuantumPhysics, #ScienceBreakthrough
https://newsletter.tf/new-proton-size-measurement-germany-physics-puzzle/
A new measurement of the proton's size is much more precise than previous ones, potentially solving a long-standing physics puzzle.
#ProtonRadius, #PhysicsNews, #StandardModel, #QuantumPhysics, #ScienceBreakthrough
https://newsletter.tf/new-proton-size-measurement-germany-physics-puzzle/
Evidence of the production of two Z bosons and a photon in proton-proton collisions is reported for the first time in CMS. The analysis uses data collected by the CMS experiment between 2016 and 2018 at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 138 fb$^{-1}$. The first evidence for the process pp $\to$ ZZ$γ$ $\to$ 4$\ellγ$ ($\ell$ = e, $μ$), with an observed (expected) significance of 3.7 (3.1) standard deviations in a fiducial region defined by $p_\mathrm{T}^γ$ $\gt$ 20 GeV, $\lvertη^γ\rvert$ $\lt$ 2.4, $ΔR(\ell,γ)$ $\gt$ 0.5, $m_\text{Z}$ between 60 and 120 GeV, and the invariant mass of either of the two Z bosons combined with the photon ($m_{\text{Z}γ}$) larger than 100 GeV, is reported. The measured (predicted) fiducial cross section is 60$^{+27}_{-22}$ ab (47.56 $\pm$ 0.04 ab). Additionally, the inclusive production of pp $\to$ 4$\ellγ$ is studied by removing the $m_{\text{Z}γ}$ requirement to include final state radiation where one Z boson decays to 2$\ellγ$, yielding an observed (expected) significance of 5.0 (4.2) standard deviations and a measured (predicted) fiducial cross section of 156$^{+39}_{-35}$ ab (99.97 $\pm$ 0.09 ab).
#MIT:
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Physicists zero in on the mass of the fundamental W boson particle
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"The team’s ultra-precise measurement confirms the Standard Model’s predictions."
https://news.mit.edu/2026/physicists-report-mass-fundamental-w-boson-particle-0408
8.4.2026
#Beschleuniger #CDF #CMS #CMSCollaboration #Fermilab #LHC #Physik #Simulation #WBoson #StandardModel #Standardmodell #Teilchenphysik #Tevatron
Evidence of the production of two Z bosons and a photon in proton-proton collisions is reported for the first time in CMS. The analysis uses data collected by the CMS experiment between 2016 and 2018 at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 138 fb$ ^{-1} $. The first evidence for the process $ \mathrm{p}\mathrm{p}\to\mathrm{Z}\mathrm{Z}\gamma\to4\ell\gamma $ ($ \ell = \mathrm{e} $, $ \mu $), with an observed (expected) significance of 3.7 (3.1) standard deviations in a fiducial region defined by $ p_{\mathrm{T}}^\gamma > $ 20 GeV, $ |\eta^\gamma| < $ 2.4, $ \Delta R(\ell,\gamma) > $ 0.5, $ m_{\mathrm{Z}} $ between 60 and 120 GeV, and the invariant mass of either of the two Z bosons combined with the photon ($ m_{\mathrm{Z}\gamma} $) larger than 100 GeV, is reported. The measured (predicted) fiducial cross section is 60 $ ^{+27}_{-22} $ ab ( 47.56 $ \pm $ 0.04 ab). Additionally, the inclusive production of $ \mathrm{p}\mathrm{p}\to4\ell\gamma $ is studied by removing the $ m_{\mathrm{Z}\gamma} $ requirement to include final state radiation where one Z boson decays to 2 $ \ell\gamma $, yielding an observed (expected) significance of 5.0 (4.2) standard deviations and a measured (predicted) fiducial cross section of 156 $ ^{+39}_{-35} $ ab ( 99.97 $ \pm $ 0.09 ab).
"Decades of weird experimental results appeared to support the existence of the sterile neutrino, a hypothetical particle that would solve multiple mysteries. But recent experiments have killed hope of finding these phantoms, leaving physicists to wonder what might explain their anomalies."
https://www.quantamagazine.org/experiments-ring-the-death-knell-for-sterile-neutrinos-20260408/
#Physics #Particles #Neutrinos #StandardModel #SterileNeutrinos
Decades of weird experimental results appeared to support the existence of the sterile neutrino, a hypothetical particle that would solve multiple mysteries. But recent experiments have killed hope of finding these phantoms, leaving physicists to wonder what might explain their anomalies.
The jet mass of W bosons decaying to a quark-antiquark pair is measured in W+jets events from proton-proton collisions at a center-of-mass energy of 13 TeV. The data used were collected by the CMS experiment at the CERN LHC and correspond to an integrated luminosity of 138 fb$^{-1}$. Hadronic decays of W bosons with high momenta produce strongly collimated decay products due to the large Lorentz boost, and are reconstructed as single large-radius jets. These jets have a characteristic substructure that is exploited to distinguish them from the large background of quark- and gluon-initiated jets. The jet mass is computed using the soft-drop algorithm, which suppresses soft wide-angle radiation that leads to a broadening of the jet mass distribution. For the first time, unfolded measurements are presented of the double-differential W+jets cross section as a function of the jet transverse momentum and soft-drop mass. From these distributions, the W boson mass is obtained, with a value of 80.83 $\pm$ 0.55 GeV, achieving the smallest uncertainty available today from an all-jets final state at a hadron collider.
The jet mass of W bosons decaying to a quark-antiquark pair is measured in W+jets events from proton-proton collisions at a center-of-mass energy of 13 TeV. The data used were collected by the CMS experiment at the CERN LHC and correspond to an integrated luminosity of 138 fb$ ^{-1} $. Hadronic decays of W bosons with high momenta produce strongly collimated decay products due to the large Lorentz boost, and are reconstructed as single large-radius jets. These jets have a characteristic substructure that is exploited to distinguish them from the large background of quark- and gluon-initiated jets. The jet mass is computed using the soft-drop algorithm, which suppresses soft wide-angle radiation that leads to a broadening of the jet mass distribution. For the first time, unfolded measurements are presented of the double-differential W+jets cross section as a function of the jet transverse momentum and soft-drop mass. From these distributions, the W boson mass is obtained, with a value of 80.83 $ \pm $ 0.55 GeV, achieving the smallest uncertainty available today from an all-jets final state at a hadron collider.
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