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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)
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.
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 :-).
I see, thanks.
added pointer to this nice set of slides
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)
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.
added pointer to
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.
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.
Today’s arXiv:1901.08290 sees the anomaly at 4sigma and suggest to explain it by an “extended Higgs sector” and right-handed neutrinos.
and then there is today’s
I don’t understand yet really the point they are making, but they point to
which I had missed earlier. This has some informative graphics from p. 10 on
Today in arXiv:1901.06380 review of the flavour anomalies as seen by the BELLE experiment, at 3.78 sigma.
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”.
also today:
more analysis of the potential lpetoquark model for flavour anomalies;
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:
and yet one more today: This article
talks about possible direct detection of the leptoquarks motived by the flavour anomalies
today in
more investigation of the possibility that the anomalies could be pointing to a Z’-boson
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”
Ah, no, apparently that channel is not a flavour anomaly, but a pentaquark resonance (arXiv:1606.06999)
added pointe to today’s
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.
Today arXiv:1902.04900 sees the effect globally at 5.3 to 5.8 sigma.
@Urs what sigma was it before?
Have a look at the entry: flavour+anomaly#StatisticalSignificance
added pointer to today’s
with more on the hypothesis that it’s a Z’-boson causing the flavour anomalies
added pointer to today’s
for when the entry becomes editable again, the following should be added:
today’s
presents new measurement results on a polarization observable in B-meson decays, and finds disagreement with the standard model at 1.7 $\sigma$, on top of the global $\sim 4 \sigma$ of the previous observables
It should become editable some time this evening European time. Apologies for the continued inconvenience.
All right, thanks a million!!
Richard, thanks for looking into this.
Let me just see if I understand where we are headed. Now it looks a little like I’ll have to incrementally rewrite parts of many nLab entries for them to work again. To be frank, that makes me feel a little overwhelmed. This affects many dozens of pages, I am afraid, and I don’t even know how to find all those affected.
And there are more tags in use.
For instance, just now I wanted to upload my slides to Equivariant Super Homotopy Theory (schreiber), for my talk tomorrow morning. But editing the entry does not work. There is an image there, which you just told me how to work around. But the parser actually complains about the div
-tag, which maybe we don’t have a workaround for yet.
I don’t have any insight into that sanitiser business, and I understand that you have good reasons not to build on that solution. But maybe just for the moment, so that we all have some time to take a step back and think about how to proceed with the security implementation, might it make sense to just implement the sanitiser, say as an intermediate hack? That would, I suppose, make the $n$Lab work and be secure for the time being, and give us time and leisure to make plans.
What do you think?
I will disable the stricter checking for the moment, so that you can upload your slides. Just a second, I’ll let you know when it’s done.
Now done, you should now be able to upload your slides. We still have the security level of #1 here in place. The new syntax still works.
Let’s continue the discussion of #35 over at that thread.
Excellent, thanks!!
added pointer to today’s review
and included a graphics from that article
added pointer to today’s
On the off-chance that anyone else is taking any interest:
Today at the main annual particle physics phenomenology meeting, Moriond 2019, they have the whole day reserved for talks about flavour anmalies, see the program here.
Given the order of events, with the big CP-violation announcement yesterday, we might get to hear some substantial news…
here is the first new announcement from today’s session
confirming the anomaly in one of the channels, now with higher accuracy.
two useful sets of review slides from yesterday’s flavour-anomaly day at Moriond:
LHCb collaboration, Search for lepton-universality violation in $B^+ \to K^+ \ell^+ \ell^-$ decays, talk at Moriond 2019 (pdf)
Ben Allanach, Finding Z’s responsible for $R_{K^{(\ast)}}$, talk at Moriond 2019 (pdf)
So it turns out that the LHCb collaboration has not yet released the bulk of their new dataset, but it’s announced for “later in 2019” – apparently they are carefully double checking something.
apparently they are carefully double checking something
good to know they are being careful. No need for another 700GeV-inspired flood of papers on a statistical blip, or superliminal neutrino right now. But if it’s solid new physics,… woohoo!
The situation is completely different to these cases.
The anomalies have been around for years, in various channels, in different experiments, with steadily increasing significance, with a well motivated theoretical explanation that, as these slides recall, gives a perfect fit to all of them.
Years before the anomalies were seen, independent researchers gave their Bayesian threshold for detection of this effect to be 3sigma, due to absence of the look-elsewhere-effect (here). Now for about a year we have been at around 3sigma in each channel and at $4.1$-sigma globally, this just confirmed yesterday with a small fraction of the new dataset.
All this is completely different from the 750GeV bump, let alone the FTL silliness. I wish people would concentrate a bit more.
Had had a wrong link in the first set of slides above (pointing to the measurement article instead of the survey slides), here is the corrected one:
But of course all this is idle entertainment for us here – except for the takeaway message: Go learn some GUT.
David, here is a CERN person making that point in #46:
This result $[$the flavour anomalies$]$ has been confirmed and confirmed over about four years now. In my book, people who complain that the LHC does not have any results or has no deviations from predictions typically are too lazy(or not good enough?) to work on this: not as easy as a diphoton peak, eh?!?
added today’s preprints, all refining the previous EFT models in light of the new data:
Marcel Algueró, Bernat Capdevila, Andreas Crivellin, Sébastien Descotes-Genon, Pere Masjuan, Joaquim Matias, Javier Virto, Addendum: “Patterns of New Physics in $b \to s \ell^+ \ell^-$ transitions in the light of recent data” (arXiv:1903.09578)
Ashutosh Kumar Alok, Amol Dighe, Shireen Gangal, Dinesh Kumar, Continuing search for new physics in $b \to \mu s s$ decays: two operators at a time (arXiv:1903.09617)
Marco Ciuchini, António M. Coutinho, Marco Fedele, Enrico Franco, Ayan Paul, Luca Silvestrini, Mauro Valli, New Physics in $b \to s \ell^+ \ell^-$ confronts new data on Lepton Universality (arXiv:1903.09632)
Thanks for the updates :-)
I meant in my slightly jokey comment above that it’s better they do the serious analysis now, rather than release some un-analysed statistical blip into the wild (not the well-observed effects you point out) and let the arXiv explode with every theory under the sun. Or, they have something very promising, and they are being careful. I’m not claiming these flavour anomalies are not real! I meant that if there’s even more interesting unexpected stuff in the data, that would be awesome.
Right, I know, but your “…no need for another…” suggested that it’s the same old nonsense, repeated. Curiously, it’s the exact opposite here: too little attention on solid data instead of too much attention on feeble data. The ways of the physics community at large is mysterious these days. Luckily, now I have a CERN expert on record agreeing with me on that :-)
Also, I think given the discussions about future particle collider projects, unwise grandstanding is not what we need, but sober and solid results.
You see, now you sound again as if we are still talking past each other: The curious thing about that inane debate about the next collider is that the flavour anomalies have largely not even been considered in this discussion, while they are one of the few actual data points on which a sensible such discussion would be based.
Something really strange is going on. The smug brainlessness of those who make their name but as bloggers is infecting the intellectual senses of a generation of otherwise clever researchers.
The ’unwise grandstanding’ applies to putative yet-unmade half-baked claims (I mean, really half-baked) based on a perceived need to come up with something flashy in a hurry, using the latest data. The ’sober and solid results’ are the kinds of things you are talking about. I really am agreeing with you on this!
All right!
On the other hand, Adam Falkowski just points out that there was one other measurement result presented at Moriond last week, which sees the statistical significance go down a fair bit, from $3.8$ to $3.1$, see slide 9 in Caria 19. Of course, this shouldn’t happen as more data comes in, if there is a true signal. So maybe it will all go away, after all…
Yeah, and now here is somebody hinting that they have upcoming refined lattice QCD computations which will make the flavour anomalies disappear (here).
added pointer to today’s preprints:
Jason Aebischer, Wolfgang Altmannshofer, Diego Guadagnoli, Meril Reboud, Peter Stangl, David M. Straub, B-decay discrepancies after Moriond 2019 (arXiv:1903.10434)
Alakabha Datta, Jacky Kumar, David London, The $B$ Anomalies and New Physics in $b \to s e^+ e^-$ (arXiv:1903.10086)
Ashutosh Kumar Alok, Dinesh Kumar, Suman Kumbhakar, S Uma Sankar, Impact of $D^\ast$ polarization measurement on solutions to $R_D - R_{D^\ast}$ anomalies (arXiv:1903.10486)
added today’s new measurement results:
added pointer to this review talk from earlier today.
The first comprehensive account of the results presented at Moriond2019 that I have seen, taking into account the new measurements both from LHCb and from Belle
also added pointer to this from last Thursday, which I had missed:
added pointer to
from earlier this week. Curiously, the latest measurements of $R_D$ by the Belle collaboration is still cited only via Caria’s talk slides for Moriond2019 (reference [1] in the article). I gather the trust in preliminary announcements of these collaborations is already the same as that in their official publication. Interesting.
I have expanded and updated the bit on the Moriond19 results. Now it reads as follows:
This situation was confirmed with the completed measurements presented at Moriond 2019, which showed (Straub 19, Allanach 19) smaller discrepancy but also with smaller uncertainty, thus keeping the statistical significance essentially unaffected. On the other hand, Caria 19, slide 9 reported an as yet unpublished measurement by the Belle collaboration by which the previous statistical significance of $3.8 \sigma$ in the $R_D$ sector would decrease to $3.1 \sigma$. Comprehensive assessments of the situation after Moriond 2019 are given in AHMSN 19, Descotes-Genon 19, Bardhan-Ghosh 19 and agree that the flavour anomalies have been confirmed:
It appears the reason is that, given the amount of independent measurements (~180!) a smaller deviation because of new physics is easier to accommodate than a large one. Thus the new measurements actually fit better with new physics.
(Axel Maas, reporting from ALPS2019 tweet, 23 Apr 2019)
added pointer to today’s
added pointer to today’s articles:
Pouya Asadi, David Shih, Maximizing the Impact of New Physics in $b \to c \tau \nu$ Anomalies, (arXiv:1905.03311)
J. E. Chavez-Saab, Marxil Sánchez, Genaro Toledo, $R_{D^\ast}$ or $R_{D_\pi}$: closing the theoretical gap? (arXiv:1905.03394)
Suman Kumbhakar, Ashutosh Kumar Alok, Dinesh Kumar, S Uma Sankar, Resolving $R_D$ and $R_{D^\ast}$ anomalies (arXiv:1905.03513)
added pointer to today’s
and
added pointer to today’s
and its precursor
which take serious the implication that the flavour anomalies point, via them pointing to leptoquarks, to GUT models
added pointer to today’s
Andrei Angelescu, Single Leptoquark Solutions to the $B$-physics Anomalies, contribution to the 2019 EW session of the 54th Rencontres de Moriond (arXiv:1905.06044)
Joe Davighi, Connecting neutral current $B$ anomalies with the heaviness of the third family, Contribution to the 2019 QCD session of the 54th Rencontres de Moriond (arXiv:1905.06073)
added pointer to today’s
added pointer to today’s hep-ph preprints:
Monika Blanke, Andreas Crivellin, Stefan de Boer, Teppei Kitahara, Marta Moscati, Ulrich Nierste, Ivan Nišandžić, Addendum: “Impact of polarization observables and $B_c \to \tau \nu$ on new physics explanations of the $b \to c \tau \nu$ anomaly” (arXiv:1905.08253)
Andreas Crivellin, Francesco Saturnino, Correlating Tauonic B Decays to the Neutron EDM via a Scalar Leptoquark (arXiv:1905.08257)
Rui-Xiang Shi, Li-Sheng Geng, Benjamín Grinstein, Sebastian Jäger, Jorge Martin Camalich, Revisiting the new-physics interpretation of the $b \to c \tau \nu$ data (arXiv:1905.08498)
That last one cites the semileptonic flavour anomalies with the words
For some time now, the ratios of semileptonic B-decay rates have appeared to be enhanced with respect to the Standard Model (SM) predictions with a global significance above the evidence threshold
and concludes more specifically:
The main conclusion is that NewPhysics interpretations driven by left-handed currents and tensor operators are favored by the data with a significance of ∼3.5σ with respect to the SM hypothesis.
added pointer to today’s
Crivellin insists again that the case for new physics is at $5 \sigma$ and claims that the latest measurements (which in one channel had just confirmed and in another channel had substantially reduced the statistical significance) actually strengthen the case for the leptoquark model
added pointer to today’s
Will add a copy of their table 2 to the entry
added pointer to today’s
added pointer to
and split off a subsection on possible relation to anomalies in the anomalous magnetic moments (here)
added pointer to today’s
David London, CP Violation in $\bar B^0 \to D^{\ast +} \ell^- \bar \nu_\ell$ (arXiv:1906.07752)
Marta Moscati, New Physics in $b \to c \tau \nu$: Impact of Polarisation Observables and $B_c \to \tau \nu$ (arXiv:1906.08035)
added today’s eloquent account:
added pointer to today’s hep-ph articles on the flavour anomalies, all on aspects of leptoquark models:
Jordan Bernigaud, Ivo de Medeiros Varzielas, Jim Talbert, Finite Family Groups for Fermionic and Leptoquark Mixing Patterns (arXiv:1906.11270)
Junichiro Kawamura, Stuart Raby, Andreas Trautner, Complete Vector-like Fourth Family and new $U(1)'$ for Muon Anomalies (arXiv:1906.11297)
Leandro Da Rold, Federico Lamagna, A vector leptoquark for the B-physics anomalies from a composite GUT (arXiv:1906.11666)
added pointer to today’s review
which again states the global statistical significance of the flavour anomalies as $5 - 6 \sigma$
added pointer to today’s
added pointer to today’s
which gives a general introduction to the topic, for readers with some basic background in QFT.
added pointer to today’s
added pointer to today’s
added pointer to
Sébastien Descotes-Genon, Alexander Khodjamirian, Javier Virto, Light-Cone Sum Rules for $B \to K \pi$ Form Factors and Applications to Rare Decays (arXiv:1908.02267)
Sebastien Descotes-Genon, Light-cone sum rules for $B \to K \pi$ form factorsand applications to rare decays, talk at bsll2019 (pdf, DescotesGenonBssl19.pdf:file)
and added the graphics from slide 13 of the latter
added point to
and their observation (p. 12) that the forecast of the LHCb collaboration for the shrinking of their error bars by 2025 holds, and the currect average values stay about the same, then the flavour anomalies will have statistical significance of 6 to 10 sigma in 2025.
added pointer to today’s
added pointer to these talk notes from earlier today:
will maybe include a slide or two of that into the entry
added pointer to last week’s
added pointer to today’s
added pointer to today’s
two reviews today, have added them:
Antonio Pich, Flavour Anomalies (arxiv:1911.06211)
David London, Anomalies in B Decays: A Sign of New Physics?, talk at XIth International Symposium on Quantum Theory and Symmetries, July 1-5, 2018 Centre de recherches mathématiques, Montréal, Canada (arxiv:1911.06238)
added pointer to today’s
Thanks for catching this. I have fixed it also at leptoquark and at GUT.
added pointer to today’s
added pointer to today’s
added pointer to this recent new measurement:
LHCb collaboration, Test of lepton universality with $\Lambda^0_b\to p K^-\ell^+\ell^-$ decays (arXiv:1912.08139)
also:
CERN courier, LHCb explores the beauty of lepton universality
(first measurement of lepton universality for $\Lambda^0_b$ Lambda baryons , finding the flavour anomaly at (only) 1 sigma but pointing in the same direction as in other channels)
added also this earlier piece regarding the above article
Finally I expanded the Idea-section to be more of an actual explanation of anything.