Cms Inwards \(Zz\) Channel: A 3-4 Sigma Show Inwards Favor Of A \(650\Gev\) Boson

Today, the CMS collaboration has revealed ane of the strongest deviations from the Standard Model inwards quite some fourth dimension inwards the paper

Search for diboson resonances inwards the semileptonic \(X \to ZV \to \ell^+\ell^- q\bar q\) end solid soil at \(\sqrt{s} = 13\TeV\) alongside CMS

On page 21, Figure 12, yous come across the Brazilian charts.




In the channel where a resonance decays to a \(ZZ\) distich together with ane \(Z\) decays to a quark-antiquark distich together with the other \(Z\)-boson to a lepton-antilepton distich (semileptonic decays), CMS folks used ii dissimilar methods to search for low-mass together with high-mass particles.




In the high-mass search – which contributed to the bottom purpose of Figure 12 – they saw a locally 2-sigma excess indicating a resonance only about \(1000\GeV\), perchance compatible alongside the novel \(\gamma\gamma\) resonance close \(975\GeV\) that appeared inwards some novel rumors nigh the 2016 data.

More impressively, the low-mass search revealed a locally 3.4 or 3.9 sigma excess inwards the search for a Randall-Sundrum or "bulk graviton" (I won't explicate the differences betwixt the ii models because I don't know the details together with I don't intend ane should accept a special interpretation also seriously) of mass \(650\GeV\). The "bulk graviton" excess is the stronger one.

Even when the look-elsewhere trial (over the \(550-1400\GeV\) range) is taken into account, equally conclusions on Page 22 indicate out, the difference is withal 2.9 or 3.5 sigma, respectively. That's pretty strong.

We may hold off for ATLAS whether they come across something. (Update: In comments, a newspaper alongside a disappointing 2-sigma deficit on that house is shown instead.) CMS has alone used 2.7 inverse femtobarns of the 2015 information inwards this analysis. Obviously, if the excess at \(650\GeV\) were real, the particle would already travel safely discovered inwards the information that receive got already been collected inwards 2015-2016 (by CMS separately) – nigh eighteen inverse femtobarns (CMS).

Concerning the \(650\GeV\) mass, inwards 2014, CMS also saw a 2.5-sigma hint of a leptoquark of that mass (more on those particles). Note that the leptoquarks acquit really dissimilar charges (quantum numbers) than the "bulk graviton".

The previous CMS papers on the same channel but based on the 2012 information were these two: low-mass, high-mass strategies. I intend that at that spot was no show inwards favor of a like hypothesis inwards those older papers. That also seems to travel truthful for the analogous ATLAS paper using the 2012 data.