Want to take part in these discussions? Sign in if you have an account, or apply for one below
Vanilla 1.1.10 is a product of Lussumo. More Information: Documentation, Community Support.
added pointer to today’s
added pointer to today’s
added pointer to today’s
added today’s publication data to
added pointer to today’s
added pointer to today’s
added pointer to today’s replacement
added pointer to todsy’s
Under Relation to other anomalies I added a graphics grabbed from today’s arXiv:2002.07184
added pointer also to this one from today:
added pointer to today’s
added pointer to today’s
added pointer to today’s
added pointer to new measurements announced today by LHCb:
Result: statistical significance of the anomaly in the channel $B^0 \to K^{\ast 0} \mu^+ \mu^-$ increases from $3.0 \sigma$ to $3.3 \sigma$
added pointer to the corresponding presentation
and included the last slide from there as a graphics into the entry
added pointer also to today’s announcement on the main CERN webpage:
added pointer to today’s CERN-Courier article:
added pointer to today’s
added pointer to today’s
added pointer to today’s
and added its Table 1 to the entry
added pointer to today’s
added pointer to today’s
added pointer to today’s
added pointer to today’s
finally added pointer to the publication
that is behind that set of slides from Moriond 2019 that has long been cited in the entry:
Then I added pointer to
which does a re-analysis of the $\mathcal{R}(D)$-anomaly including these new measurements (still finds a discrepancy of world averages in this channel at $\sim 3 \sigma$ statistical significance)
added pointer to today’s
added pointer to today’s
added pointer to today’s
added pointer to these recent talk notes:
Niels Tuning, Recent results from LHCb, Nikhef 2020 (nikhef event:2253, pdf)
In recent years a number of results in flavour physics have drawn some attention due to tensions with respect to Standard Model predictions. An overview of these results will be shown, together with a few recent results from this Spring, both on the flavour anomalies and ’classical’ flavour physics
added publication data for:
added pointer to today’s
added pointer to today’s
added pointer to today’s
added pointer to today’s
added pointer to today’s
(these last three go in a section “hadronic decays” which might eventually want to be on a separate page)
added pointer to today’s
added pointer to today’s
added pointer to today’s
added pointer to today’s
added pointer to today’s
added today’s announcement of a new measurement, confirming the flavour anomaly at $3.1 \sigma$, now also in $B^+$-decays:
added pointer to today’s
In the Standard Model Effective Theory (SMEFT) [41, 42], the significance of NewPhysics from the global $b \to s \ell^+ \ell^-$ analysis increases with the inclusion of new data, reaching a maximum of almost 6σ for the simple hypothesis of a non-vanishing $[$leptoquark contribution$]$.
added pointer to today’s
added pointer to today’s
and to its precursor
added pointer to today’s
added pointer to today’s
Added pointer to today’s review:
I have added pointer to today’s survey of the state of the matter:
and included the following quote (their emphasis!):
Both $R_K$ and $P'_5$ have moved towards the Standard Model, but this actually improves the New Physics fits.
The set of $b \to s \ell \ell$ anomalies are alive and a global coherence remains after the measurements in 2019 and 2020. While some key measurements have central values that have moved towards the Standard Model predictions, the overall consistency of the data and the global tension with respect to the Standard Model has not diminished (in fact this may even enhance the significance for New Physics). The New Physics fit is a good fit (with $p$-values in the ballpark of 50%), and the SM pull is high $[$…$]$. In addition, data sets from all different experiments are compatible $[$…$]$.
added pointer to today’s
added pointer to todays’s
with the quote:
Naive combination of $R_K$ and $R_{K*}$ measurements shows a deviation from the standard model above $4 \sigma$
added pointer to today’s
with this quote:
We find that the data on clean observables is at variance with the SM at a level of $3.9 \signa$. Furthermore, scenarios withpure left-handed or axial currents provide a better desciption of these data with a significance close to $5 \sigma$.
with this quote:
With the recent updates $[...]$ the case for new physics inrare B decays has been further strengthened. $[...]$ Even if only the theoretically clean LFU observables $[...]$ are considered, muon specific $[$ Wilson coefficients for New Physics$]$ im prove over the Standard Model by $\sqrt{\Delta^2} \simeq 4.7 \sigma$.
It looks like the floodgates are opening up now. Let’s see how much longer I can keep up with logging the development.
Added pointer to today’s:
with this quote:
With the recent result $[$ of LHCb $]$, for the first time a single observable affected by negligible theoretical uncertainties exhibits a deviation from the SM exceeding the $3 \sigma$ level. Equally striking is the overall coherence of the picture that emerges, especially in $b \to s \ell^+ \ell^-$ −transitions. As we shall show in this paper, combining all the $b \to s \ell^+ \ell^-$−observables in a very conservative way, the significance of the New Physics (NP) hypothesis formulated in 2014–2015 of a purely left-handed LFU-violating contact interaction has now reached a significance of $4.6 \sigma$.
$[\ldots]$ A more structural way of addressing the flavor structure of the model is the idea of implementing Pati-Salam unification
added pointer to this little video with Gino Isidori giving his impression on the flavour anomalies:
Textbook account:
added pointer to the recent:
added pointer to today’s
which claims to do a new and more careful analysis of the global statistical significance of the flavour anomalies (and finds $3.9 \sigma$)
added pointer to
with this quote:
the combined significance of the deviation reaches $4.7\sigma$. Furthermore,taking into account also less theoretically-clean observables $[\ldots]$ the overall significance of the deviations in this channel is raised to even above $6\sigma$, depending on the specific SM prediction employed
added pointer to today’s
added pointer to today’s
with this quote:
From the global fits to various $b \to s l^+ l^-$−data, the discrepancy is more than $5\sigma$ from the SM predictions. The new result (59) further strengthens the lepton flavor universality violation. This anomaly alone convincingly indicates New Physics
Added pointer to today’s
including this quote:
A highly conservative method for combining the various $b \to s \ell \ell$ anomalies, including the look-elsewhere effect, estimates their global significance to be 3.9σ. The combined set of discrepancies are by and large self-consistent with a common new physics origin involving muons.
The other day I had added pointer to these recent slides:
which give a more comprehensive/pedagogical discussion than usual
added pointer to today’s
added pointer to today’s
with this quote, from the abstract:
Motivated by $[\cdots]$ LHCb’s new measurements $[\cdots]$ we quantify the combined level of discrepancy with the Standard Model and fit values of short-distance Wilson coefficients. A combination of the clean observables $R_K$, $R_{K^\ast}$, and $B_s \to \mu \mu$ alone results in a discrepancy with the Standard Model at $4.0 \sigma$, up from $3.5 \sigma$ in 2017. One-parameter scenarios with purely left-handed or with purely axial coupling to muons fit the data well and result in a $\sim 5 \sigma$ pull from the Standard Model.
added pointer to today’s:
added this pointer
with a link to a recent talk by Isidori (here)
added pointer to today’s new measurement result:
(Apparently it’s another but small addition to the emerging pattern, see here. Though from this graphics it looks rather convincing.)
added pointer to today’s
For when the editing functionality is back, to add these pointers:
Some days ago, Isidori et al. further strengthened their claim that the flavour anomalies point to a Randall-Sundrum model with 3-branes:
highlighted again today in the review:
(Noteworthy that these authors are not string theorists but pure HEP phenomenologists. They just went for the best fit of the data seen in the flavour anomalies.)
Luckily today
was updated, which reminded me to include it. Added the following quote (here)
We critically analyze the body of results that hints to the existence of New Physics from possible violations of lepton universality observed by the LHCb experiment. $[\cdots]$ the deviations from the Standard Model are at the 4.7σ level when including only the hadronic insensitive observables while it increases to 6.1σ when including also the hadronic sensitive ones.
$[...]$ Scalar leptoquarks, either a singlet or a doublet of weak interactions, can explain all the anomalies.
added pointer to this new textbook:
(though it doesn’t seem really published/available yet)
added pointer to today’s review:
together with this quote (from the abstract):
The main final message is that all the instruments necessary to fully establish the putative new effects are at hand, thanks to running experiments and their upgrades. Therefore this subject stands concrete chances to usher genuinely unexpected discoveries.
added pointer to today’s review:
(no real news, except that the picture remains – reference to experimental hint for GUTs now commonplace)
added pointer to
(which was updated on the arXiv today) and added (under “Updates in 2022”, here) this quote:
when combining all tests of LFUV (like $R_{K^+}$ ) with $B$ decays involving muon pairs […], one finds a preference for new physics (NP) hypotheses of more than 7σ compared to the SM. Note that such a high significance is only possible since all measurements are compatible with each other, i.e. they form a coherent picture
also added (under “Relation to other anomalies” here) the following remark:
In ACMM22 it is argued (see footnote 3) that also the huge anomaly reported by CDF collaboration 2022 in the mass of the W-boson is compatible with (in fact predicted by) the $B$-meson decay anomalies.
almost missed this announcement when being on vacation:
have added the pointer now, together with this quote:
We have used our improved scalar, vector and tensor form factors calculated in $N_f = 2+1+1$ lattice QCD […] Our improved form factors significantly sharpen the tension, which becomes particularly strong in the region below the charmonium resonances. For $1.1 \lt q^2 \lt 6 GeV^2$ we find a tension of 4.7σ for $B^+ \to K^+ \mu^+ \mu^-$ and 3.6σ for $B^0 \to K^+ \mu^+ \mu^-$ with LHCb ’14A and 3.3σ for $B^+ \to K^+ e^+ e^-$ with LHCb ’21
So that’s now $4.7 \sigma$ in a single channel.
added pointer to today’s
together with this quote:
The updated NP fits to rare B decays […] follow the same trend as with the previous set of results favouring in particular new physics contributions in the Wilson coefficient $C^\mu_9$, with an increased significance. […] The projections for clean observables, show that if the current tensions remain, $R_K$ can establish NP with 5σ significance already with less than 20 $fb^{-1}$ of data. The main source of theory uncertainty in global fits is due to non-local hadronic contributions. However, different fits with different setups, inputs and statistical frameworks show a remarkable agreement so that the experimental observation of the discrepancy in these observables would be a clear sign of physics beyond the SM.
added pointer to today’s
added pointer to yesterday’s new measurement announcement by LHCb:
(upshot: previous analyses of the flavour anomaly in the $R(D)$-channel confirmed)
added pointer to today’s
together with this quote from their conclusion:
We present the first fully relativistic determination of the scalar, vector and tensor form factors for $B \to K$ decays. […] Using these form factors, we can calculate the SM branching fraction for $B \to K e(\mu)+ e(\mu)^-$ […] We find tensions above $3\sigma$ in the ratio of our result with LHCb, and above $5\sigma$ in one instance for the low $q^2$ bin.
added pointer to:
together with quotes (here) of the new $\sigma$s they state in their conclusions:
present data deviates from the SM predictions at 4.3σ
also added pointer to:
added pointer to today’s
together with a quote of the first couple of paragraphs
added pointer to today’s
added pointer to the recent:
which claims that re-analysis of hadronic backgrounds in kaonic decays makes the decay rate in the electron channel go down, so that the ratio $R_K$, $R_{K^\ast}$ over the corresponding muon channel is accurately described by the standard model (cf. A. Maas, 20 Dec 2022).
This here is more explicit:
added pointer to today’s
who accordingly conclude:
that current data no longer provide strong hints for NP.
I have linked to this from a new subsection Fixing the backgrounds.
But it looks like it’s time to close this thread. Sorry for all the noise.
(I was prepared to eventually be disappointed. But the way this ends up being disappointing is itself disappointing.)