Simply put, any protophobic boson makes no sense. Protons are composite objects, and there is no plausible reason for a fundamental boson to be "phobic" towards one kind of hadron produced by quarks and gluons, but not another. The authors' suggestion that such an explanation is "probable" is using a poor definition of that term.
The so-called X17 particle has been proposed in order to explain a very significant resonant behaviour (in both the angular separation and invariant mass) of e+e− pairs produced during a nuclear transition of excited 8Be, 4He and 12C nuclei. Fits to the corresponding data point, as most probable explanation, to a spin-1 object, which is protophobic and has a mass of approximately 16.7 MeV, which then makes the X17 potentially observable in Coherent Elastic neutrino (ν) Nucleus Scattering (CEνNS) at the European Spallation Source (ESS).
By adopting as theoretical framework a minimal extension of the Standard Model (SM) with a generic U(1)′ gauge group mixing with the hypercharge one of the latter, which can naturally accommodate the X17 state compliant with all available measurements from a variety of experiments, we predict that CEνNS at the ESS will constitute an effective means to probe this hypothesis, even after allowing for the inevitable systematics associated to the performance of the planned detectors therein.
Joakim Cederkäll, et al., "Hunting the elusive X17 in CEνNS at the ESS" arXiv:2509.15121(September 18, 2025).
Feng explains protophobic here
ReplyDeletehttps://arxiv.org/pdf/1604.07411
which then makes the X17 potentially observable in Coherent Elastic neutrino (ν) Nucleus Scattering (CEνNS) at the European Spallation Source (ESS).
I wonder how soon these results will come in. there's more than a dozen experiments attempting to validate or disprove x17 , including Montreal Tandem accelerator
https://www.researchgate.net/publication/366260185_Status_of_the_X17_search_in_Montreal
η→γe+e−η→γe+e− at HIAF
Probing the ATOMKI X17 vector boson using Dalitz decays V→Pe+e−V→Pe+e−
Measurement of angular correlations in low-energy internally-created e−e+ pairs using Timepix3 pixel detectors
A new detection set-up to search the X17 boson
"An excess of electron-positron pairs at large relative angle emitted in the 3H(p,e+e−)4He, 7Li(p,e+e−)8Be, and 11B(p,e+e−)12C nuclear processes has been recently observed. These anomalies are compatible with the creation of a boson with mass of about 17 MeV, not foreseen in the standard model. To probe the possible existence of the so called X17 boson, we propose to study for the first time the 3He(n,e+e−)4He reaction at the n_TOF facility at CERN. The experimental program and performance of the detector prototype are discussed."
Searches for Sub-GeV Dark Matter with NOvA and LDMX and Performance Studies of the Cosmic-Ray Veto for Mu2e
among others.
while its possible they will rule it out, it also possible they may confirm it.
what would you say if Coherent Elastic neutrino (ν) Nucleus Scattering (CEνNS) at the European Spallation Source (ESS) provides a 5 sigma confirmation signal of x17? of course its also possible other experiments will rule it out. PADME and MEGII gave opposite results. both have upgraded their detectors and plan to do another run with more data taking.
Given the large number of experiments devoted to x17, its being taken very seriously by a large number of HEP experimentalist
Resorting to BSM physics to explain this obscure correlation doesn't make sense when there are SM explanations and when we don't really understand the internal structure of atomic nuclei with three or more nucleons well. It doesn't show up, for example, in much simpler contexts like W and Z boson decays.
DeleteBy adopting as theoretical framework a minimal extension of the Standard Model (SM) with a generic U(1)′ gauge group mixing with the hypercharge one of the latter, which can naturally accommodate the X17 state compliant with all available measurements from a variety of experiments, we predict that CEνNS at the ESS will constitute an effective means to probe this hypothesis, even after allowing for the inevitable systematics associated to the performance of the planned detectors therein.
ReplyDeletesounds Confidence Inspiring to me, and they will look for it CEνNS at the ESS
what is your opinion of U(1)′ gauge group mixing with the hypercharge
Any thoughts on this?
ReplyDeletehttps://www.ladbible.com/news/science/scientists-signal-parallel-universe-reason-701545-20250923
This is the paper: https://arxiv.org/abs/2509.07831
ReplyDeleteThanks for providing the link.
Delete@Ryan the article's title is "Scientists explain terrifying reason they think we received a signal from parallel universe" and no we didn't. Traversable wormholes aren't real, let alone traversable wormholes to other universes, and as the lay article explains: "To be pretty clear before we start diving into this theory of other universes sending us signals, the preferred interpretation of the event is that it was some kind of black hole collision."
ReplyDelete