{"id":1061,"date":"2008-11-02T23:59:07","date_gmt":"2008-11-03T04:59:07","guid":{"rendered":"http:\/\/www.math.columbia.edu\/~woit\/wordpress\/?p=1061"},"modified":"2009-04-15T09:12:10","modified_gmt":"2009-04-15T14:12:10","slug":"the-circus-begins","status":"publish","type":"post","link":"https:\/\/www.math.columbia.edu\/~woit\/wordpress\/?p=1061","title":{"rendered":"The Circus Begins"},"content":{"rendered":"

Friday’s arXiv posting of the paper by CDF about the multi-muon anomaly<\/a> they are seeing has already generated three different conjectural explanations of what physics might be responsible for this. Undoubtedly many, many more are on the way.<\/p>\n

  • Some members of the CDF collaboration have posted a paper entitled Phenomenological interpretation of the multi-muon events reported by the CDF collaboration<\/a>. This explains the large numbers of muons with a rather baroque mechanism, conjecturing the production of a 300 GeV heavy particle decaying through a chain of 3 lighter particles, the last of which is supposed to be the long-lived (20 picosecond) one. This interpretation was part of the original draft PRL from last June\/July. The CDF collaboration as a whole seems to have decided not to support the draft PRL and this interpretation, instead releasing just a PRD paper that describes the anomaly without trying to interpret its significance. It also seems that only two-thirds of the collaboration put their names on the PRD paper, and the interpretation paper was put out just by a small group. The whole story is somewhat reminiscent of the “Superjet” affair (see Tommaso Dorigo’s multi-part discussion here<\/a>), which also involved a PRD publication about an anomaly signed by the collaboration, and an interpretation (in terms of squarks) signed by a much smaller group led by Paolo Giromini.<\/li>\n
  • An hour or so after the Giromini et. al. paper came in on Friday, a group of string theorists had posted the 40-page Towards Realistic String Vacua<\/a> on hep-th claiming to explain the CDF results with a class of string vacua:
    \n

    We also describe model-independent physical implications of this scenario. These include the masses of anomalous and non-anomalous U(1)’s and the generic existence of a new hyperweak force under which leptons and\/or quarks could be charged. We propose that such a gauge boson could be responsible for the ghost muon anomaly recently found at the Tevatron’s CDF detector. <\/p><\/blockquote>\n

    If the Giromini et. al. explanation invoking 4 new particles is baroque, it’s hard to know what the right word is for the far more complicated constructions that are described in this paper.\n<\/li>\n

  • There’s a new version this evening of the 3-week old Arkani-Hamed\/Weiner LHC Signals for a SuperUnified Theory of Dark Matter<\/a>, in which they claim to have a new signature for supersymmetry, with a large fraction of all SUSY events looking exactly like what CDF described. Oddly enough, the changes to the paper don’t include a mention of the CDF result. This paper also invokes a rather baroque mechanism, involving both the supersymmetric extension of the standard model and a whole new complicated dark sector.<\/li>\n

    This last paper is also supposed to explain the PAMELA data, and papers with other explanations of this are starting to flood hep-ph.<\/p>\n

    So far, all the explanations of the anomaly seen by CDF look suspiciously complicated, which may be one reason that many members of CDF are so skeptical about the whole thing that they were unwilling to sign on to the PRD submission. But I’m sure that many more proposals for how to explain the anomaly are being drafted at this very moment, and maybe one of them will be more convincing.<\/p>\n

    Update<\/strong>: Over at Tommaso Dorigo’s blog there’s a short posting about Giromini et. al.<\/a>, and an exchange with Nima Arkani-Hamed<\/a>, who claims to have had no inside knowledge of the CDF “lepton jets” when he wrote his paper with Weiner predicting them. He also explains how the exact mechanism discussed in that paper is unlikely to explain the CDF result since their observed rate is too high for this.<\/p>\n

    Update<\/strong>: New Scientist has the story<\/a>, emphasizing the possible relation to the work of Arkani-Hamed and Weiner:<\/p>\n

    So what could it be? As it happens, Weiner and Nima Arkani-Hamed of the Institute for Advanced Study in Princeton, New Jersey, and colleagues have developed a theory of dark matter \u2013 the enigmatic stuff thought to make up a large proportion of the universe \u2013 to explain recent observations of radiation and anti-particles from the Milky Way.<\/p>\n

    Their model<\/a> posits dark matter particles that interact among themselves by exchanging “force-carrying” particles with a mass of about 1 gigaelectronvolts.
    \nThe CDF muons appear to have come from the decay of a particle with a mass of about 1 GeV. So could they be a signature of dark matter? “We are trying to figure that out,” says Weiner. “But I would be excited by the CDF data regardless.”<\/p><\/blockquote>\n

    CDF spokesperson Jacobo Konigsberg is quoted as saying:<\/p>\n

    we haven’t ruled out a mundane explanation for this, and I want to make that very clear<\/p><\/blockquote>\n

    Update<\/strong>: Then there’s Slashdot<\/a>, where the hypothetical CDF particle is advertised as accounting for the Arkani-Hamed et. al. theory of dark matter.<\/p>\n

    Update<\/strong>: Another story, at Physics World<\/a>, which has more from various people at CDF. Again, that Arkani-Hamed\/Weiner “predicted a CDF\u2013like signal”, although the problem with the rate being too low is mentioned.<\/p>\n

    Also Nature<\/a>, where one learns:<\/p>\n

    Theorists are already coming up with ideas about what might be producing the excess muons. One possibility is that they stem from the decay of a heavier, yet-to-be-discovered particle \u2014 perhaps related to dark matter, an unseen material that is believed to make up some 85% of matter in the Universe.<\/p>\n

    Another idea from string theory evokes seven-dimensional ‘branes’ \u2014 theoretical surfaces that are inhabited by exotic particles manifested as strings. These higher-dimensional branes might be home to force-carrying particles that interact weakly with our three-dimensional world and create a faint, but traceable, signal in the data.<\/p>\n

    But Adam Falkowski, a theorist at CERN, Europe’s particle accelerator laboratory near Geneva, Switzerland, says that the explanations need some work, and cautions against attempting to force the data to fit into particular theories.<\/p><\/blockquote>\n

    Update: More press stories here<\/a> and here<\/a>.<\/p>\n","protected":false},"excerpt":{"rendered":"

    Friday’s arXiv posting of the paper by CDF about the multi-muon anomaly they are seeing has already generated three different conjectural explanations of what physics might be responsible for this. Undoubtedly many, many more are on the way. Some members … Continue reading →<\/span><\/a><\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_post_was_ever_published":false},"categories":[9],"tags":[],"class_list":["post-1061","post","type-post","status-publish","format-standard","hentry","category-experimental-hep-news"],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/www.math.columbia.edu\/~woit\/wordpress\/index.php?rest_route=\/wp\/v2\/posts\/1061","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.math.columbia.edu\/~woit\/wordpress\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.math.columbia.edu\/~woit\/wordpress\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.math.columbia.edu\/~woit\/wordpress\/index.php?rest_route=\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.math.columbia.edu\/~woit\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=1061"}],"version-history":[{"count":18,"href":"https:\/\/www.math.columbia.edu\/~woit\/wordpress\/index.php?rest_route=\/wp\/v2\/posts\/1061\/revisions"}],"predecessor-version":[{"id":1840,"href":"https:\/\/www.math.columbia.edu\/~woit\/wordpress\/index.php?rest_route=\/wp\/v2\/posts\/1061\/revisions\/1840"}],"wp:attachment":[{"href":"https:\/\/www.math.columbia.edu\/~woit\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=1061"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.math.columbia.edu\/~woit\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=1061"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.math.columbia.edu\/~woit\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=1061"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}