The measurement of the W boson produced by the CMS of the LHC rules the anomaly at 7 sigma of the CDF II of the Tevatron

2024-09-17 17:14:33

In particle physics, the big news of 2022 is the size of the W boson measured by the Tevatron’s CDF II detector, 80 433.5 ± 9.4 MeV/c², the most precise measurement, but 7 sigma from the standard model (LCMF, 08 April 2022) ; It generates a lot of doubt, as I said in my speech at Naukas Bilbao 2022 (LCMF, September 16, 2022). Everyone is waiting for the CMS measurement from the LHC, which has been working since 2014. Today the result was announced at a conference in CERN, the measurement 80 360.2 ± 9.9 MeV / c², in perfect agreement with the standard model, 80,357 ± 6 MeV /c². 16.8 fb⁻¹ of the collisions at 13 TeV cm collected during 2016 have been observed lepton decay of the W boson into a muon and a muon neutrino; The analysis is very difficult because the neutrino is not detected, only the loss in the line loss (pT) is estimated. The analytical procedure has been validated using “W-type” decays of the Z boson into a muon and an antimuon, in which one of the two muons is replaced by the loss of a linear loss (imitating what was observed for the W boson); A value of 91 182 ± 14 MeV/c² was obtained, in good agreement with the standard model 91188.0 ± 2.0 MeV/c². Without a doubt, the standard model comes out much stronger by this new dimension. Now the ball is in CDF’s court, how can you explain the reason for your anonymous result.

October 16, 2016 event on CMS (Compact Muon Solenoid) shows the decay of the W boson into a muon (red above) and a neutrino (not observed, but marked with a purple arrow). CMS is a detector of about 13,000 tons in the form of a multi-layer cylinder about 21 meters long and 16 meters in diameter. The inner layer is silicon detectors for charged particle tracks (in yellow), which is surrounded by electromagnetic scintillation calorimeter (in green) and hadronic calorimeters (not shown in the figure, they will be in blue). These levels are in the middle of a 3.8 Tesla superconducting solenoid, 13 meters long and 6 meters in diameter that bends the path of charged particles (in yellow). Outside (red) are the muon detectors, the key to the mass of new matter; It should be noted that the great precision of CMS when calculating the trajectory, energy and recoil of muons is important for calculating the recoil of the unobserved neutrino. The detection of muons in CMS is measured with the decays of J/ψ → µµ mesons (although the decays of the Υ(1S) beautiful mesons and the Z boson can be used independently).

This figure shows the results for calculations of the size of the Z boson (left) using “W-type” decays, which lead to the result 91 182 ± 7 (stat) ± 12 (syst) MeV/c², and of The mass of the W boson (right), 80 360.2 ± 2.4 (stat) ± 9.6 (syst) MeV/c², is the largest new result. The fields are data and scientific statistics (including N³LL and NNLO predictions) appear in color. The same analytical algorithm has been used to estimate the mass of W and Z bosons, although the lowest return cutoff for muons has been pT > 24 GeV/c for W and pT > 26 GeV/c for Z (because your reason). to its great extent). I do not want to go into further details of the analysis (those who are interested can refer to Appendix A of the article, pages 20–53, which shows all the details).