tag:blogger.com,1999:blog-2846514233477399562.post2334937387036315216..comments2024-01-08T09:37:04.406+01:00Comments on RÉSONAANCES: D0: top forward-backward asymmetry continues to intrigueJesterhttp://www.blogger.com/profile/08947218566941608850noreply@blogger.comBlogger10125tag:blogger.com,1999:blog-2846514233477399562.post-67507164961692812472011-07-26T22:22:33.088+01:002011-07-26T22:22:33.088+01:00As to the 23 July 2011 Nature News article by Ron ...As to the 23 July 2011 Nature News article by Ron Cowen saying: <br />"... Christopher Hill ... proposed how a top quark and its antiparticle could impart mass to the W and Z bosons ...". <br /><br />Such Higgs as Tquark Condensate structures have been described by Yamawaki and Hashimoto and Tanabashi in papers at <br />hep-ph/9603293 and hep-ph/0311165 <br />which discuss: <br /><br />a Bardeen-Hill-Lindner model allows calculation of Higgs mass as around 240 GeV which is in the 250 GeV region of a (statistically small as of now) peak found by both ATLAS and CMS. <br />Physically, this might correspond to the edge of vacuum stability and the Higgs VEV <br />and<br />a variant (similar to a Kaluza-Klein Nambu-Jona-Lasinio model) allows calculation of Higgs mass as around 176-188 GeV which is near the 205 GeV region of a peak (even smaller statistically) found by both ATLAS and CMS. <br />Physically, this might correspond to the edge of the Triviality Boundary. <br /><br />TonyTony Smithhttp://www.valdostamuseum.org/hamsmith/noreply@blogger.comtag:blogger.com,1999:blog-2846514233477399562.post-58468265084607078862011-07-26T20:56:20.289+01:002011-07-26T20:56:20.289+01:00Spinned. I mean, topcolor is a valid model, even i...Spinned. I mean, topcolor is a valid model, even if a bit on the baroque side, and all these topgluons and toppions can well produce the asymmetry. But there's nothing in the data that favors this particular model.Jesterhttps://www.blogger.com/profile/08947218566941608850noreply@blogger.comtag:blogger.com,1999:blog-2846514233477399562.post-82394059440857999282011-07-26T19:31:50.988+01:002011-07-26T19:31:50.988+01:00The Nature News article is promoting top quark con...The Nature News article is promoting top quark condensation as a possible explanation. Is this a reasonable interpretation, or did the reporter get spinned by some theorists?Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-2846514233477399562.post-65970883972189228112011-07-26T17:58:40.855+01:002011-07-26T17:58:40.855+01:00I'm just waiting to see the new CDF result. I&...I'm just waiting to see the new CDF result. I've been told the significance rises. But my spies don't give any more details.<br /><br />So, I don't think it's a fluke. Perhaps a matter of unfolding.JAnoreply@blogger.comtag:blogger.com,1999:blog-2846514233477399562.post-8735369334795719772011-07-26T15:47:48.882+01:002011-07-26T15:47:48.882+01:00I agree. That's why I wrote a couple of ifs. (...I agree. That's why I wrote a couple of ifs. (I think the idea of the particle below threshold is nice also for other reasons, but I'm biased.)Manolohttps://www.blogger.com/profile/05958280067411409499noreply@blogger.comtag:blogger.com,1999:blog-2846514233477399562.post-68855055023870145562011-07-26T14:05:00.200+01:002011-07-26T14:05:00.200+01:00Right, if there's no mtt dependence of the asy...Right, if there's no mtt dependence of the asymmetry, that'd be a game-changer. But I would not jump to conclusions. A reasonable possibility is that CDF has a 1 sigma upward fluke while D0 has a downward one. A milder mtt dependence actually makes model building easier.Jesterhttps://www.blogger.com/profile/08947218566941608850noreply@blogger.comtag:blogger.com,1999:blog-2846514233477399562.post-30520539539026797272011-07-26T12:49:24.195+01:002011-07-26T12:49:24.195+01:00Hi Jester,
It looks like D0 does not trust the &q...Hi Jester,<br /><br />It looks like D0 does not trust the "coarse" unfolding of CDF, which was employed to arrive at the famous three-sigma anomaly in the asymmetry for mtt>450. CMS does not dare to unfold their mass-dependent results yet, either. <br /><br />If we forgot that CDF result for a moment (even if it has been kindly feeding theorists these months), things would really look pretty different. D0 (and CMS) results seem to hint to a flat profile in the invariant mass. If that turns out to be true, almost all of the new-physics models that have been proposed so far will be dead (many have been killed already by LHC, anyway), since they predict an asymmetry that increases neatly with mtt.<br /><br />The one exception I know is our proposal of a very light gluon-like particle, with mass below the t tbar production threshold, exchanged in the s channel. This guy gives a flat (or gently rising) shape of the Tevatron FB asymmetry and of the charge asymmetry at LHC. Moreover, it does not distort the invariant mass distribution of the cross section, neither at Tevatron nor at LHC, so it is almost invisible. I hope some people will investigate this simple idea further.<br /><br />Cheers!Manolohttps://www.blogger.com/profile/05958280067411409499noreply@blogger.comtag:blogger.com,1999:blog-2846514233477399562.post-26868978870532204822011-07-26T10:16:05.070+01:002011-07-26T10:16:05.070+01:00The LHC sees no mass-dependent asymmetry so far (s...The LHC sees no mass-dependent asymmetry so far (see Monday afternoon t talk)Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-2846514233477399562.post-86409239017828569232011-07-26T06:09:58.646+01:002011-07-26T06:09:58.646+01:00I see that D0 refers to this paper on a Z' exp...I see that D0 refers to <a href="http://arxiv.org/abs/1101.5625" rel="nofollow">this paper</a> on a Z' explanation with strong quark coupling. Amusingly, the paper is sufficiently recent to hedge its bets about any of the usual Z' suspects.Keahttps://www.blogger.com/profile/05652514294703722285noreply@blogger.comtag:blogger.com,1999:blog-2846514233477399562.post-57676447631118039562011-07-26T03:42:54.000+01:002011-07-26T03:42:54.000+01:00Why are you so depressed?
Finally nature is forci...Why are you so depressed?<br /><br />Finally nature is forcing us to question our fundamental assumptions.<br /><br />The vacuum energy density crisis, the wildly unnatural Planck mass, the lack of an explanation for alpha and h-bar, and all those 26-30 parameters that have to be put into the SM "by hand" have been screaming at us for decades that there is something seriously wrong at the heart of particle physics.<br /><br />Time for courage and open minds.<br /><br />In the words of Monty Python: time for something completely different.<br /><br />And none too soon.<br /><br />RLO<br />http://www3.amherst.edu/~rloldershawRobert L. Oldershawhttps://www.blogger.com/profile/15396555790655312393noreply@blogger.com