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• CommentRowNumber1.
• CommentAuthorUrs
• CommentTimeOct 16th 2018

am starting some minimum here. Have been trying to read up on this topic. This will likely become huge towards beginning of next year

• CommentRowNumber2.
• CommentAuthorDavidRoberts
• CommentTimeOct 16th 2018
• (edited Oct 16th 2018)

Huge for your work, or huge for external reasons, or no comment?

Edit: oh, I guess there will some CERN announcement on certain results around then (and presumably hundreds of theory papers shortly afterwards proposing solutions :-P)

• CommentRowNumber3.
• CommentAuthorUrs
• CommentTimeOct 16th 2018

Didn’t mean to be cryptic, sorry. Am writing from mostly offline family vacation.

If the Run 2 data analysis of the B meson decay experiments at the LHC confirms the Run 1 data, which seems rather likely, it is apparently clear already that the further data will serve to push the statistical significance of the observed flavour anomaly, which currently is around 3 sigma (= heads up but let’s double-check) to well over 5 sigma (= discovery, call the press), which would make it the first detection of genuinely “new physics” at the LHC which the hep community is longing for so badly.

Besides the new particle hiding here, it may be of interest for further development of the field that the effect comes not from the traditional direct detection scattering experiments, but from “precision measurement” of anomalies in comparatively low energy decays which reveal high energy particles in the form of “virtual” intermediate processes. This approach towards hep phenomenology (virtual high energy particles seen indirectly by precision measurement of low energy processes) may be the future of hep experiments beyond LHC.

• CommentRowNumber4.
• CommentAuthorUrs
• CommentTimeOct 27th 2018

• CommentRowNumber5.
• CommentAuthorUrs
• CommentTimeDec 30th 2018

added more references and explicit pointers to the statement of an effect at around $4 \sigma$ confidence

• CommentRowNumber6.
• CommentAuthorUrs
• CommentTimeJan 1st 2019

• CommentRowNumber7.
• CommentAuthorRichard Williamson
• CommentTimeJan 1st 2019
• (edited Jan 1st 2019)

It doesn’t really matter, but apparently use of the HTML <center> tag is deprecated in HTML 5, so I replaced it with use of the new LaTeX centring syntax :-).

• CommentRowNumber8.
• CommentAuthorUrs
• CommentTimeJan 1st 2019

I see, thanks.

• CommentRowNumber9.
• CommentAuthorUrs
• CommentTimeJan 16th 2019

added pointer on possible explanation via leptoquarks (here)

• CommentRowNumber10.
• CommentAuthorUrs
• CommentTimeJan 20th 2019

added pointer to this nice set of slides

• Francesca Dordei, Lepton flavour universality at LHCb, August 2018 (cern:2634813, pdf)
• CommentRowNumber11.
• CommentAuthorUrs
• CommentTimeJan 22nd 2019
• (edited Jan 22nd 2019)

added a bunch of further pointers.

references by Andreas Crivellin stand out. In Crivellin 18, published one month ago (pos.sissa.it/321/269), the author speaks of “compelling evidence for New Physics” (p. 2)

• CommentRowNumber12.
• CommentAuthorUrs
• CommentTimeJan 23rd 2019

clarified the distinction between the claimed \gt 5 \sigma\$ significance of all decay channels jointly, over that of each channel separately

• CommentRowNumber13.
• CommentAuthorUrs
• CommentTimeJan 23rd 2019
• (edited Jan 23rd 2019)

added here the two tables by Lyons and Dorigo, kindly pointed out by David C., which argue that the detection-threshold for the significance of the flavour anomaly is at $3 \sigma$ and hence a) much lower than the conventional $5 \sigma$ and b) long exceeded by the experimental signal.

• CommentRowNumber14.
• CommentAuthorUrs
• CommentTimeJan 23rd 2019

• Jacky Kumar, David London, New physics in $b \to s e^+ e^-$? (arXiv:1901.04516)

from a few days ago.

They now quote a statistical significance of up to $6 \sigma$, but I didn’t figure out where exactly they take that value from.

• CommentRowNumber15.
• CommentAuthorUrs
• CommentTimeJan 23rd 2019
• (edited Jan 23rd 2019)

The recent arxiv:1901.04761 seems to see the significance at 5.8 sigma (though I admit I don’t know what that “pull”-terminology is saying, here and elsewhere?) and tries to explain it with a dark matter particle. Somehow.

• CommentRowNumber16.
• CommentAuthorUrs
• CommentTimeJan 25th 2019
• (edited Jan 25th 2019)

Today’s arXiv:1901.08290 sees the anomaly at 4sigma and suggest to explain it by an “extended Higgs sector” and right-handed neutrinos.

• CommentRowNumber17.
• CommentAuthorUrs
• CommentTimeJan 25th 2019

and then there is today’s

• Domagoj Leljak, Blazenka Melic, Monalisa Patra, On lepton flavour universality in semileptonic $B_c \to \eta_c, J/\psi$ decays (arXiv:1901.08368)

I don’t understand yet really the point they are making, but they point to

• Monika Blanke, Andreas Crivellin, Stefan de Boer, Teppei Kitahara, Marta Moscati, Ulrich Nierste, Ivan Nišandžić, Impact of polarization observables and $B_c \to \tau \nu$ on new physics explanations of the $b \to c \tau \nu$ anomaly (arXiv:1811.09603)

which I had missed earlier. This has some informative graphics from p. 10 on

• CommentRowNumber18.
• CommentAuthorUrs
• CommentTimeJan 28th 2019

Today in arXiv:1901.06380 review of the flavour anomalies as seen by the BELLE experiment, at 3.78 sigma.

• CommentRowNumber19.
• CommentAuthorUrs
• CommentTimeJan 31st 2019

Today’s arXiv:1901.10484 claims that if one assumes the putative leptoquark to respect certain residual abelian flavour symmetries of the Yukawa couplings (which apparently is plausible when asking for UV-completion of the model) then not only is the resulting fit to the flavour anomaly data “excellent” but also the remaining choices become very constrained, making the leptoquark explanation of the flavour anomalies “extremely predictive”.

• CommentRowNumber20.
• CommentAuthorUrs
• CommentTimeJan 31st 2019

also today:

more analysis of the potential lpetoquark model for flavour anomalies;

• Michael J. Baker, Javier Fuentes-Martin, Gino Isidori, Matthias König, High-pT Signatures in Vector-Leptoquark Models (arXiv:1901.10480)

and a replacement from last month on how the same leptoquark that could explain the flavour anomalies might also explain the anomalies seen at the ANITA experiment:

• Bhavesh Chauhan, Subhendra Mohanty, A common leptoquark solution of flavor and ANITA anomalies (arXiv:1812.00919)
• CommentRowNumber21.
• CommentAuthorUrs
• CommentTimeJan 31st 2019

• Natascia Vignaroli, Seeking leptoquarks in the $t \bar t$ plus missing energy channel at the high-luminosity LHC (arXiv:1808.10309)

talks about possible direct detection of the leptoquarks motived by the flavour anomalies

• CommentRowNumber22.
• CommentAuthorUrs
• CommentTimeFeb 5th 2019
• (edited Feb 5th 2019)

today in

• G. D’Ambrosio, A. M. Iyer, F. Piccinini, A.D. Polosa, Confronting $B$ anomalies with atomic physics (arXiv:1902.00893)

more investigation of the possibility that the anomalies could be pointing to a Z’-boson

• CommentRowNumber23.
• CommentAuthorUrs
• CommentTimeFeb 7th 2019
• (edited Feb 7th 2019)

New measurements by LHCb reported today in (arXiv:1902.02092) for one of the decay channels. It concludes by saying the 2.8sigma discrepancy found earlier by ATLAS in this channel is confirmed, but “with higher precision”

• CommentRowNumber24.
• CommentAuthorUrs
• CommentTimeFeb 7th 2019

Ah, no, apparently that channel is not a flavour anomaly, but a pentaquark resonance (arXiv:1606.06999)

• CommentRowNumber25.
• CommentAuthorUrs
• CommentTimeFeb 11th 2019

• Srimoy Bhattacharya, Aritra Biswas, Zaineb Calcuttawala, Sunando Kumar Patra, An in-depth analysis of $b \to c(s)$ semileptonic observables with possible $\mu \to \tau$ mixing (arXiv:1902.02796)

We thus conclude that the models IV and V, while still incapable of a satisfactory explanation of $R(K^\ast)_{Low}$, is not only allowed by the plethora of flavor observables, but also is of high statistical significance, with quite a precise prediction for effective Wilson coefficients, providing a possible path-way for future model builders. High precision experiments inthe coming days will illuminate the map even further.

• CommentRowNumber26.
• CommentAuthorUrs
• CommentTimeFeb 14th 2019

Today arXiv:1902.04900 sees the effect globally at 5.3 to 5.8 sigma.

• CommentRowNumber27.
• CommentAuthorAlizter
• CommentTime7 days ago

@Urs what sigma was it before?

• CommentRowNumber28.
• CommentAuthorUrs
• CommentTime7 days ago

Have a look at the entry: flavour+anomaly#StatisticalSignificance

• CommentRowNumber29.
• CommentAuthorUrs
• CommentTime2 days ago

• P. Ko, Takaaki Nomura, Chaehyun Yu, $b \to s \mu^+ \mu^-$ anomalies and related phenomenology in $U(1)_{B_{3-x_\mu L_\mu - x_\tau L_\tau}}$ flavor gauge models (arXiv:1902.06107)