Recent Experimental Measurements Of Standard Model Constants

W Boson Mass At The LHC (ATLAS) and Tevatron (CDF)

The result of the CDF analysis is MW = 80 387±12(stat.)±15(syst.) MeV; the result of the ATLAS analysis is MW = 80 370 ± 7(stat.) ± 11(exp.syst.) ± 14(mod.syst.) MeV. The total uncertainty is 19 MeV in both analyses.

From here.

My comments: The lighter ATLAS result is closer to a result expected from a global electroweak fit. The Tevatron based results will never get better because that experiment has concluded. The LHC based results will almost surely get better before the experiment concludes, if for no other reason, because the statistical error will get a bit smaller over time and because independent results from ATLAS and CMS can be combined reducing a little systemic error as well.

Heavy Quark Masses And The Strong Coupling Constant From HERA

New results on the measurements of the hadronic final state in neutral-current deep-inelastic scattering at HERA are presented. A combination of reduced charm and beauty cross sections is presented and the masses of the heavy quarks are determined to mc=1290(+78−53)MeV and mb=4049(+138−118)MeV. The measurement of the production of prompt photons accompanied by a jet provides a precise test of QCD predictions. Measurements of jet production cross sections are presented and compared for the first time to next-to-next-to-leading order predictions (NNLO). The strong coupling constant is determined from inclusive jet and dijet production cross sections using NNLO predictions to αs(mZ)=0.1157(6)exp(+31−26)th.

My comments: The charm quark mass is a bit high, (also here and here) and bottom quark mass is a bit on the low side, as is the strong force coupling constant. But, all of the measurements have significant margins of error, so the differences aren't very meaningful.

CKM Matrix Elements Involving Bottom Quarks At Belle II

Semileptonic B meson decays involving low-mass charged leptons e or μ are expected to be free of non-Standard Model contributions and therefore play a critical role in determinations of |Vub|and |Vcb|. Of all the CKM matrix parameters, |Vub| is the least precisely measured and in most need of additional studies in order to better constrain the apex of the Unitarity Triangle. We focus on exclusive reconstruction of charmless semileptonic B meson decay B→πℓν, and present prospects and estimates for measuring |Vub| at Belle II with the full planned dataset of 50 ab−1 of integrated luminosity.

My comments: These two element are hard to measure because Vtb = 0.99914 +/- 0.00005 is dominant, and Vub = 0.00355 ± 0.00015, in particular, is very small. The square of Vub which represents the probability is 1.26 per 100,000. The paper discusses prospects for improvements in accuracy in future measurements of this CKM matrix elements and does not actually contain any measurements.

UPDATE May 18, 2017: A survey of recent measurements of four CKM matrix elements is found here. END UPDATE.

Theoretically Expected Higgs Boson Diphoton Decays

Physicists have replicated, in a more general matter than a previous result, the conclusion that many of the terms that go into calculating the likelihood that a Higgs boson will experience a diphoton decay cancel out. In particular, they show "the cancellation of all terms among the Feynman diagrams which are to be integrated to give divergences higher than logarithmic." This conclusion which requires 30 dense pages of calculations implies that calculating the likelihood of this decay is much easier than would be naively expected.

Faeries And Iron

Theory that fairies are scared of metal due to the metal wielding Beaker invasion crushing the Neolithics.

The theory above in a tweet by Miles @mgdever is interesting but probably wrong. 

The Bell Beaker culture brought copper and bronze to Britons in the stone age, but the legendary aversion of fairies to metal is specifically an aversion to iron, with fairies sometimes wielding Bronze weapons.

The British Iron Age, however, started around 800 BCE, which is at a point when the Bronze Age culture brought by the Bell Beaker movement has collapsed and was being replaced by Celtic culture, although probably not with much population replacement.

The relatively shallow time depth of the Celtic languages supports the case for a language shift in Western Europe to the Celtic languages with the associated culture in the Iron Age, even though we know that there wasn't much population genetic replacement at that time. Proto-Celtic is often associated with the Urnfield archaeological culture. This implies that the original language of the Bell Beaker people has been lost except as a substrate in the Celtic language, and possibly in the Basque language (one of several theories).

A Possible Etymology Of "Cannabis"

The Aramaic phrase qaneh bosm (קְנֵה-בֹשֶׂם) "cannabis" (literally "aromatic cane") may be the ultimate source of the word "Cannabis" in English. Egyptians and other Afro-Asiatic language family speakers are known to have used hemp as a fiber plant, so the sourcing has some corroboration.

More detail, with pre-Greek Minoan as a possible bridge language, here.

Ancient Turtles Were Huge

At the dawn of the Holocene era, about 10,000 years ago, turtles as big as this one still existed on Earth.

The enormous giant tortoise Megalochelys atlas shows just how big it was compared to Rey. (Image by Jan Freedman)

Get the whole story at Twilight Beasts.

Some B Meson Decay Anomalies Disappear In Run-2 Data

The LHCb had detected a four sigma anomaly from the expected decays of B mesons into decays including two leptons of opposite charge in Run-1. But, the anomaly appears to have vanished once Run-2 data is included (original formatting of preprint abstract retained).

This is a big deal, because real anomalies, unlike experimental errors or flukes, should be significantly stronger when the size and robustness of the data set increases, not less significant. Anomalies the decline in significance as more data is collected are almost always flukes or experimental errors even if the results are sufficiently significant that they might otherwise constitute a notable anomaly.

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)

After Run 1 of the LHC, global fits to b→sℓℓ observables show a deviation from the Standard Model (SM) with a significance of ∼ 4 standard devations. An example of a b→sℓℓ process is the decay of a B0s meson into two muons (B0s→μ+μ−). The latest analysis of B0(s)→μ+μ− decays by LHCb with Run 1 and Run 2 data is presented. The B0s→μ+μ− decay is observed for the first time by a single experiment. In addition, the first measurement of the B0s→μ+μ−effective lifetime is performed. No significant excess of B0→μ+μ− decays is observed. All results are consistent with the SM and constrain New Physics in b→sℓℓ processes.

Not every single pathway that is the subject of the anomalies tending to show lepton non-universality in B meson decays is ruled out by this result, but is does disfavor these hints of beyond the Standard Model physics.

Another result disfavoring the anomaly in B meson decays is here. So do these experiments. And these experiments. And these experiments. And these experiments. It is also disfavored by the frequency of Higgs boson decays to tau leptons.

Thus, while there is some experimental data that seems to show anomalies, finding a theory that can accommodate these data points while simultaneously being consistent with the substantial experimental evidence tending to show that there are not violations of lepton flavor universality, is quite challenging. As a result, even though the anomaly is putatively a four sigma effect, it is probably really just a statistical fluke, or a consequence of underestimating systemic error or look elsewhere effects, or is a consequence of a mistake in conducting the experiment or analyzing it.