Tuesday, November 22, 2022

Resolving The Tevatron W Boson Mass Anomaly While Saving Face

A group reworking old Tevatron collider measurements of the W boson mass announced a result in April of 2022 that was anomalously high. It was so high that it is basically inconsistent with all other measurements of it (including previous Tevatron measurements) and with a global Standard Model fit.

Now, a collaboration between Tevatron scientists and Large Hadron Collider (LHC) scientists has published a paper that as obliquely as possible, so as to save face for the Tevatron scientists, explains why their previous announcement was too high (which everyone except desperate theorists have basically known since the outset, even if many of them didn't say so out loud), so that the embarrassing debacle of the initial results announcement can be salvaged to provide something of value to science.

The body text of the conference paper, however, suggests that the first step will only reduce the Tevatron W boson mass measurement by about 10 MeV which is still too little, although it helps easy the tension and there is apparently a second installment of adjustments still to come.
We present the current status of the W-boson mass averaging project, an ongoing effort aimed at combining Tevatron and LHC measurements. Methods are presented to accurately evaluate the effect of PDFs and other modelling variations on existing measurements. Based on this approach, the measurements can be corrected to a common modelling reference and to the same PDFs, and subsequently combined accounting for PDF correlations in a quantitative way. We discuss the combination procedure, and the impact of improvements in the theoretical description of W-boson production and decay.
Simone Amoroso (on behalf of the Tevatron/LHC W-mass combination Working Group), "Status of the W-boson mass averaging project" arXiv:2211.12365 (November 22, 2022) (Contribution to the proceedings of the 41st International Conference on High Energy Physics (ICHEP2022), 6-13 July 2022, Bologna, Italy).


neo said...

your thoughts on this -- Status of the X17 search in Montreal

they'll verify or refuses a clear signal after about two weeks of data taking with a 2 μA proton beam

if verify first new BSM physics

[Submitted on 21 Nov 2022]

Status of the X17 search in Montreal


G. Azuelos, B. Broerman, D. Bryman, W.C. Chen, H.N. da Luz, L. Doria, A. Gupta, L-A. Hamel, M. Laurin, K. Leach, G. Lefebvre, J-P. Martin, A. Robinson, N. Starinski, R. Sykora, D. Tiwari, U. Wichoski, V. Zacek

At the Montreal Tandem accelerator, an experiment is being set up to measure internal pair creation from the decay of nuclear excited states using a multiwire proportional chamber and scintillator bars surrounding it from the DAPHNE experiment. The acceptance covers a solid angle of nearly 4π. Preamplifiers and the data acquisition hardware have been designed and tested. The water-cooled 7LiF target, mounted on an Al foil is in a thin carbon fiber section of the beamline. The experiment will focus at first on a measurement of the internal pair creation from the 18.15 MeV state of 8Be. Assuming the ATOMKI evaluation of the electron-pair production rate from X17, a Geant4 simulation predicts observation of a clear signal after about two weeks of data taking with a 2 μA proton beam. The IPC measurement could eventually be extended to the giant dipole resonance of 8Be, as well as to other nuclei, in particular to 10B.

Comments: 5 pages, 4 figures, Proceedings contribution, TRIUMF Ariel Workshop, May 25-27 2022 Subjects: Instrumentation and Detectors (physics.ins-det); Nuclear Experiment (nucl-ex) Cite as: arXiv:2211.11900 [physics.ins-det]
(or arXiv:2211.11900v1 [physics.ins-det] for this version)

 [Submitted on 16 Oct 2022]

ARIEL experiments and theory

Petr Navratil

I present an overview of experiments at TRIUMF ARIEL and ISAC facilities covering both the current and the future envisioned programs. I also briefly review theory program at TRIUMF that relates to the ARIEL experimental program. I highlight several recent experimental results from the nuclear astrophysics, nuclear structure, fundamental symmetries, and the sterile neutrino search. Finally, I mention ongoing theoretical ab initio calculations of the proton capture on 7Li related to the X17 boson observation.

Comments: Contribution to proceedings of the workshop New Scientific Opportunities with the TRIUMF ARIEL e-linac, 10 pages, 5 figures

Subjects: Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)

Cite as: arXiv:2210.08438 [nucl-th]

[Submitted on 29 Sep 2022]


andrew said...

The X17 isn't real. These experiments will confirm other work already ruling it out.

neo said...

we'd get answers to that by 2023

These experiments are fined tuned for x17 unlike earlier ones

what If in 2023 X17 is real.

neo said...

if in 2023 Montreal Tandem accelerator confirm x17 would you accept it

neo said...

if in 2023 Montreal Tandem accelerator or other like padme rules out x17 i would accept it