"All results are consistent with the Standard Model (SM) and constrain New Physics..."

... but statistical fluctuations would not be unexpected

In the SM, Flavour Changing Neutral Currents (FCNCs) occur at loop level and are suppressed by the GIM mechanism, and sometimes helicity suppression. As New Physics (NP) is not necessarily suppressed, FCNCs probe physics at energies beyond the LHC centre-of-mass energy. One such FCNC is the b → sℓℓ transition. Several theory groups have performed global fits to b → sℓℓ observables in the Effective Field Theory (EFT) framework, and find that the data deviate by ∼ 4 standard deviations with respect to the SM...  

Here, the new LHCb analysis of B⁰₍ₛ₎→µ⁺+µ⁻ observables is presented. It is based on data corresponding to an integrated luminosity of 1 fb⁻¹  of pp collisions at a centre-of-mass energy of √s = 7 TeV, 2 fb⁻¹  at √ s = 8 TeV and 1.4 fb⁻¹ at √s = 13 TeV. The first two datasets are referred to as Run 1, the latter as Run 2... 

The B⁰ₛ→µ⁺+µ⁻ decay is observed with a significance of 7.8 standard deviations, and its branching fraction is measured to be B(B⁰ₛ→µ⁺+µ⁻) = (3.0±0.6+0.3 −0.2)×10⁻⁹, where the first uncertainty is statistical and the second systematic. In addition, the first measurement of the B⁰ₛ→µ⁺+µ⁻ effective lifetime is performed: τ(B⁰ₛ→µ⁺+µ⁻) = 2.04± 0.44±0.05 ps. No significant excess of B⁰→µ⁺+µ⁻ decays is observed, and a 95% confidence level upper limit is determined, B(B⁰→µ⁺+µ⁻)<3.4×10⁻¹⁰. All results are consistent with the SM and constrain New Physics in b → sℓℓ processes.

– (left) Mass distribution of selected B⁰ₛ→µ⁺+µ⁻ candidates in the four most sensitive BDT bins. The result of the fit is overlaid. (right) The 2D confidence interval in B⁰ₛ→µ⁺+µ⁻, B⁰→µ⁺+µ⁻ from this measurement.

The branching fraction and effective lifetime of B0(s)→μ+μ− at LHCb with Run 1 and Run 2 data

Mick Mulder, for the LHCb Collaboration

(Submitted on 9 May 2017)

Just a reminder

Even though the CKM picture appears to be in excellent agreement with the data overall (Fig.2), new physics may still affect a subset of observables. Theoretically, there is no preference for the scale of fundamental flavor dynamics: it may be at the TeV scale, in which case it must be very special, or just as well at the Planck scale as is the case in string theory. Given that the flavor structures we see in the SM are special, one should keep an open mind and be prepared for surprises. Having said that, it is important to appreciate the sheer volume of B–physics data: the B+ meson already has close to 500 decay modes, such that statistical fluctuations would not be unexpected...

The highlights and take–home lessons from Moriond QCD 2017 can be summarized by the following bullet points: 

• remarkable progress in precision calculations. NNLO precision is now a commonplace allowing for unprecedented accuracy at a hadron machine. 

• Higgs precision era. Higgs pT distributions, interference effects, etc. allow for accurate tests of the Higgs nature. 

• intriguing B–physics anomalies. Several 2 − 3σ deviations in clean semi-leptonic observables leave ample room for new physics. [While ... anomaly {in some observable} is driven by the LHCb data, {others} show... deviations of varying significance in all three experiments: BaBar, Belle and LHCb... more statistics is needed to see if the current tendency persists] 

• data–driven theory: test “unmotivated” ideas. Given the absence of striking signatures of “traditional” forms of new physics, the theory approach should be more inclusive. May require painstaking analysis of difficult observables. 

Moriond QCD 2017: theoretical summary

Oleg Lebedev

(Submitted on 28 Apr 2017 (v1), last revised 10 May 2017 (this version, v2))

A last periphrase*  personal comment 

Amending the concluding point of O. Lebedev in his summary article, one could write the following. Given the absence of striking signatures of traditional forms of new particle physics, the theory approach may be more inclusive. It should require challenging the traditional extensions of physical spacetime studied up to now and considering some recent theoretical results that make it possible to watch on the blind spot (understand more fundamentally the phenomenological aspect) of quantum non-abelian gauge theories with spontaneous symmetry breaking in the light of the possible connection of Higgs mechanism with gravity, possibly shedding new light on the dark sector(s) of astrophysics.

*last edit : May 26 2017