Friday, 20 March 2015

Friday wrap-up: Higgs mass combination, ttH, LHCb rumour...

Wherein I list some (mostly) recent happenings, ramble a bit, and provide links, in an order roughly determined by importance and relevance to particle physics. Views are my own. Content very definitely skewed by my own leanings and by papers getting coverage, and it may not even be correct. It is a blog after all...

  • Long Shutdown (LS1) is over, and we should have the first fully circulating beam next week!

    You can track LHC and CMS status here and even view live events. CMS are currently doing their cosmic run with the magnet only turned up a couple of days ago; I managed to catch a nice one bending in the B field:


  • The ATLAS/CMS preliminary Higgs mass combination was presented for the first time at Moriond (talk here [pdf]). The result is $$m_H=125.09\pm0.24\, [\pm0.21\text{ (stat.)}\pm0.11\text{ (syst.)] GeV}$$

  • ATLAS has submitted their results on $t\bar{t}H$ production with $H\to b\bar{b}$ and released a Conf Note on $H\to WW,\tau\tau,ZZ$. Both see a small excess over the SM (of some interest only because CMS has $\mu_{ttH}$ at $>2\sigma$ above SM). I assume that those results enter into the following plot also presented in the Moriond talk(?). At least it is something to keep half an eye on in Run 2, while it likely goes away...


  • Also released for Moriond are new results on Higgs decays to dark photons: both $H\to\gamma_d\gamma_d\to 4l$ and $H\to Z\gamma_d\to 4l$ (talk here [pdf]). Nothing seen, but a nice result, especially looking into Run 2 when they are likely to explore significant parameter space for the Higgsed dark photon model.
  • There's a rumour (via Jester) that the LHCb $B\to K^*\mu\mu$ analysis for the full 3/fb of data is due out soon, and it confirms the anomaly already observed in the previous analysis. If it is today then that would line up with the heavy flavour day at Moriond. See these-two Resonaances posts for an easily digestible recap, or dig deeper with any of these...

    Edit: Now confirmed; significance $\approx 3.7\sigma$... see LHCb news and the talk slides [pdf]. Below is new result (black) and old result (blue). Conf Note out soon.


  • Super-Kamiokande has set the best limits on spin-dependent dark matter annihilating indirectly to neutrinos in the Sun.


  • Quanta Magazine has an interview with Steven Weinberg which touches on his view of the history of science and where it's at now, including some discussion on the multiverse.
  • In video/audio media:
    • Dancing in the Dark documentary on the LHC and dark matter is on BBC iPlayer for the next month or so [60 minutes], and a radio programme as well [43 minutes].
    • A video about the LHC from Fermilab featuring Don Lincoln. [6 minutes]
    • It was Super Pi Day last week... here is ViHart's anti Pi Day rant. [4 minutes]
    • Visualisation of today's upcoming eclipse from NASA Goddard. [2 minutes]
    • Hunting new craters on the moon, from NASA Goddard. [5 minutes]
  • NASA's Mars Atmosphere and Volatile Evolution (MAVEN) spacecraft has observed two unexpected phenomena in the Martian atmosphere: an unexplained high-altitude dust cloud and aurora that reaches deep into the Martian atmosphere. No mention in the NASA release or the Nature News, but I wonder if perhaps they are seeing again the plumes that hit the news a few weeks back?

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