Comments on: Guest post: Ben Allanach, “Predictions for SUSY Particle Masses” http://dorigo.wordpress.com/2008/09/04/guest-post-den-allanach-predictions-for-susy-particle-masses/ private thoughts of a physicist and chessplayer Sun, 29 Nov 2009 21:30:30 +0000 http://wordpress.com/ hourly 1 By: Ben Allanach http://dorigo.wordpress.com/2008/09/04/guest-post-den-allanach-predictions-for-susy-particle-masses/#comment-100627 Ben Allanach Mon, 22 Sep 2008 12:46:16 +0000 http://dorigo.wordpress.com/?p=1458#comment-100627 I should point out that the Bayesian fits in terms of the CMSSM parameters in <a href="http://arxiv.org/abs/0705.2012" rel="nofollow">arXiv:0705.2012</a> are very similar to the Bayesian results in our paper, despite the fact that most of the sub-programs used are different to ours (with the notable exception of <a href="http://projects.hepforge.org/softsusy/" rel="nofollow">SOFTSUSY</a>). In Bayesian fits, one finds that the dark matter constraint makes the largest difference, above and beyond all other constraints, contrary to what happens in the frequentist interpretation in Buchmueller et al's results. I should point out that the Bayesian fits in terms of the CMSSM parameters in arXiv:0705.2012 are very similar to the Bayesian results in our paper, despite the fact that most of the sub-programs used are different to ours (with the notable exception of
SOFTSUSY).
In Bayesian fits, one finds that the dark matter constraint makes the largest difference, above and beyond all other constraints, contrary to what happens in the frequentist interpretation in Buchmueller et al’s results.

]]> By: Ben Allanach http://dorigo.wordpress.com/2008/09/04/guest-post-den-allanach-predictions-for-susy-particle-masses/#comment-100246 Ben Allanach Mon, 08 Sep 2008 12:39:39 +0000 http://dorigo.wordpress.com/?p=1458#comment-100246 Hi Sven, no I agree that it's not that large - qualitatively, they are similar. Still, a factor of 2 in m0 reach is quite a difference.... Best, Ben Hi Sven,

no I agree that it’s not that large – qualitatively, they are similar.
Still, a factor of 2 in m0 reach is quite a difference….
Best,
Ben

]]> By: Sven Heinemeyer http://dorigo.wordpress.com/2008/09/04/guest-post-den-allanach-predictions-for-susy-particle-masses/#comment-100242 Sven Heinemeyer Mon, 08 Sep 2008 08:15:34 +0000 http://dorigo.wordpress.com/?p=1458#comment-100242 Hi Ben, this is of course not the place to have a detailed comparison between different analyses. Therefore just one comment: our best-fit point is accidentally very close to SPS1a. This point always had a Higgs mass of about 114 GeV (for a top quark mass of 175 GeV). We find a mass that is a bit lower, probably mostly due to the lower top mass of 172.4 GeV. I do not think that the differences between your analysis (the one you did 'our way') and ours are that large. We show how different treatments of e.g. the errors of (g-2)_mu or BR(b -> s gamma) can influence the range in m_0 and m_1/2. This was actually one of the three main points in our paper. Cheers, Sven Hi Ben,
this is of course not the place to have a detailed comparison between different analyses. Therefore just one comment: our best-fit point is accidentally very close to SPS1a. This point always had a Higgs mass of about 114 GeV (for a top quark mass of 175 GeV). We find a mass that is a bit lower, probably mostly due to the lower top mass of 172.4 GeV.

I do not think that the differences between your analysis (the one you did ‘our way’) and ours are that large. We show how different treatments of e.g. the errors of (g-2)_mu or BR(b -> s gamma) can influence the range in m_0 and m_1/2. This was actually one of the three main points in our paper.

Cheers, Sven

]]> By: Ben Allanach http://dorigo.wordpress.com/2008/09/04/guest-post-den-allanach-predictions-for-susy-particle-masses/#comment-100213 Ben Allanach Sat, 06 Sep 2008 10:13:19 +0000 http://dorigo.wordpress.com/?p=1458#comment-100213 Dear Nicola, thanks for pointing these papers out. It does appear that the boost factors needed are really large (they're quoting 10000 in the case of SUSY, and 100 for other models). The thick plottens.... Best, Ben Dear Nicola,

thanks for pointing these papers out. It does appear that the boost factors needed are really large (they’re quoting 10000 in the case of SUSY, and 100 for other models).

The thick plottens….
Best,
Ben

]]> By: Luboš Motl http://dorigo.wordpress.com/2008/09/04/guest-post-den-allanach-predictions-for-susy-particle-masses/#comment-100199 Luboš Motl Fri, 05 Sep 2008 19:01:11 +0000 http://dorigo.wordpress.com/?p=1458#comment-100199 Dear Ben, I agree that their program is the more natural one to do the comparison, because 1) new papers should explain their relationship to the old ones that they should know, and because 2) it should be easier to modify a program they played with recently. Concerning the "falsifications" by predicting too light a Higgs, pure Standard Model is even worse, with the optimum Higgs mass being near 85 GeV. In this sense, Nature seems to be even more supersymmetric than MSSM. ;-) Best Lubos Dear Ben,

I agree that their program is the more natural one to do the comparison, because 1) new papers should explain their relationship to the old ones that they should know, and because 2) it should be easier to modify a program they played with recently.

Concerning the “falsifications” by predicting too light a Higgs, pure Standard Model is even worse, with the optimum Higgs mass being near 85 GeV. In this sense, Nature seems to be even more supersymmetric than MSSM. ;-)

Best
Lubos

]]> By: Nicola http://dorigo.wordpress.com/2008/09/04/guest-post-den-allanach-predictions-for-susy-particle-masses/#comment-100185 Nicola Fri, 05 Sep 2008 15:12:41 +0000 http://dorigo.wordpress.com/?p=1458#comment-100185 Hi Ben, look also this http://arxiv.org/abs/0808.3867 (Cirelli, Strumia) and this one http://arxiv.org/abs/0808.3725 (Bergstrom et al.) Despite their claim to explain the e+ excess in terms of SUSY particles annihilations, the so-called astrophysical "boost factor" is still needed to match the data... and other astrophisical contributions (eg e+ from pulsar) are poorly known. So, without any drop in the spectrum, I would say that puzzle seems to be still unsolved... Hi Ben, look also this
http://arxiv.org/abs/0808.3867 (Cirelli, Strumia)
and this one
http://arxiv.org/abs/0808.3725 (Bergstrom et al.)
Despite their claim to explain the e+ excess in terms of SUSY particles annihilations, the so-called astrophysical “boost factor” is still needed to match the data… and other astrophisical contributions (eg e+ from pulsar) are poorly known.
So, without any drop in the spectrum, I would say that puzzle seems to be still unsolved…

]]> By: Ben Allanach http://dorigo.wordpress.com/2008/09/04/guest-post-den-allanach-predictions-for-susy-particle-masses/#comment-100177 Ben Allanach Fri, 05 Sep 2008 13:22:13 +0000 http://dorigo.wordpress.com/?p=1458#comment-100177 Just a quick update on the difference: my research student Matt Dolan checked the Buchmueller et al best fit point through our machinery, and got a Higgs mass of 109 GeV, which would be quite disfavoured by LEP2. Since our calculation uses SOFTSUSY and the other group uses FeynHiggs, I wonder if the discrepancy lies within this observable? Just a quick update on the difference: my research student Matt Dolan checked the Buchmueller et al best fit point through our machinery, and got a Higgs mass of 109 GeV, which would be quite disfavoured by LEP2. Since our calculation uses SOFTSUSY and the other group uses FeynHiggs, I wonder if the discrepancy lies within this observable?

]]> By: Ben Allanach http://dorigo.wordpress.com/2008/09/04/guest-post-den-allanach-predictions-for-susy-particle-masses/#comment-100172 Ben Allanach Fri, 05 Sep 2008 11:17:59 +0000 http://dorigo.wordpress.com/?p=1458#comment-100172 "What do you think of the surprising rise in CR e+ spectrum found by PAMELA satellite (and recently “stolen” by Italian theoreticians)? It seems to be the most direct proof about the particle dark matter observed in CRs." I'd agree: it's a fascinating result. Of course the "smoking gun" would be if at higher energies, the positron fraction drops off rapidly and we see the background re-emerging. I understand that <a href="http://pamela.roma2.infn.it/index.php" rel="nofollow">Pamela</a> can increase their reach by about a factor of 2. I should think it's worth a post by Tommaso: the only place I've seen a representation of the data is in a <a href="http://arxiv.org/abs/0809.0162" rel="nofollow">phenomenology paper</a>. “What do you think of the surprising rise in CR e+ spectrum found by PAMELA satellite (and recently “stolen” by Italian theoreticians)?
It seems to be the most direct proof about the particle dark matter observed in CRs.”

I’d agree: it’s a fascinating result. Of course the “smoking gun”
would be if at higher energies, the positron fraction drops off rapidly and we see the background re-emerging. I understand that Pamela can increase their reach by about a factor of 2. I should think it’s worth a post by Tommaso: the only place I’ve seen a representation of the data is in a phenomenology paper.

]]> By: Ben Allanach http://dorigo.wordpress.com/2008/09/04/guest-post-den-allanach-predictions-for-susy-particle-masses/#comment-100171 Ben Allanach Fri, 05 Sep 2008 11:13:26 +0000 http://dorigo.wordpress.com/?p=1458#comment-100171 Reply To: "Cannot each team, for example, rerun their algorithm with the same set of quantities (and the same values and error margins) that the other group used, to check their (two papers’) mutual compatibility?" This can be done of course - the problem is that it is a lot of work for my team. A lot less work would be for Buchmueller et al to just have a look at points they have already sampled to see the effect of their additional variables. I feel justified in asking them to do this, since theirs is the new paper, and readers may expect a comparison/explanation of differences with previous literature. The hypothesis of an error in one of our calculations could of course be true, but there may hopefully be a more legitimate reason. Reply To:
“Cannot each team, for example, rerun their algorithm with the same set of quantities (and the same values and error margins) that the other group used, to check their (two papers’) mutual compatibility?”

This can be done of course – the problem is that it is a lot of work for my team. A lot less work would be for Buchmueller et al to just have a look at points they have already sampled to see the effect of their additional variables. I feel justified in asking them to do this, since theirs is the new paper, and readers may expect a comparison/explanation of differences with previous literature.
The hypothesis of an error in one of our calculations could of course be true, but there may hopefully be a more legitimate reason.

]]> By: Haelfix http://dorigo.wordpress.com/2008/09/04/guest-post-den-allanach-predictions-for-susy-particle-masses/#comment-100165 Haelfix Fri, 05 Sep 2008 03:30:02 +0000 http://dorigo.wordpress.com/?p=1458#comment-100165 They could probably recompile with the additional updated top mass and electroweak constraints if they had computer time but including additional b and k physics could require some moderatedly long recoding and perhaps algorithm changes. Either way they're pretty darn close (and its purely academic since we will know anyway in a few months), but given the usual sensitivity to the top mass, I suspect they'd be very nearly equivalent with updated data. They could probably recompile with the additional updated top mass and electroweak constraints if they had computer time but including additional b and k physics could require some moderatedly long recoding and perhaps algorithm changes.

Either way they’re pretty darn close (and its purely academic since we will know anyway in a few months), but given the usual sensitivity to the top mass, I suspect they’d be very nearly equivalent with updated data.

]]> By: Nicola http://dorigo.wordpress.com/2008/09/04/guest-post-den-allanach-predictions-for-susy-particle-masses/#comment-100162 Nicola Thu, 04 Sep 2008 21:04:14 +0000 http://dorigo.wordpress.com/?p=1458#comment-100162 Hi, What do you think of the surprising rise in CR e+ spectrum found by PAMELA satellite (and recently "stolen" by Italian theoreticians)? It seems to be the most direct proof about the particle dark matter observed in CRs. Hi,
What do you think of the surprising rise in CR e+ spectrum found by PAMELA satellite (and recently “stolen” by Italian theoreticians)?
It seems to be the most direct proof about the particle dark matter observed in CRs.

]]> By: Luboš Motl http://dorigo.wordpress.com/2008/09/04/guest-post-den-allanach-predictions-for-susy-particle-masses/#comment-100161 Luboš Motl Thu, 04 Sep 2008 19:39:03 +0000 http://dorigo.wordpress.com/?p=1458#comment-100161 Ciao Tommaso, I would actually be very surprised if the Camgrid required more than a weekend to draw one of these 2D charts. At any rate, is science still supposed to be reproducible? ;-) Best Lubos Ciao Tommaso,

I would actually be very surprised if the Camgrid required more than a weekend to draw one of these 2D charts. At any rate, is science still supposed to be reproducible? ;-)

Best
Lubos

]]> By: dorigo http://dorigo.wordpress.com/2008/09/04/guest-post-den-allanach-predictions-for-susy-particle-masses/#comment-100160 dorigo Thu, 04 Sep 2008 19:25:30 +0000 http://dorigo.wordpress.com/?p=1458#comment-100160 Hi Lubos, these calculations are horribly CPU intensive. It usually requires a lot of babysitting, not a weekend job I would say. Of course I am just guessing, Ben probably will have something to say about this. Cheers, T. Hi Lubos,

these calculations are horribly CPU intensive. It usually requires a lot of babysitting, not a weekend job I would say. Of course I am just guessing, Ben probably will have something to say about this.

Cheers,
T.

]]> By: Luboš Motl http://dorigo.wordpress.com/2008/09/04/guest-post-den-allanach-predictions-for-susy-particle-masses/#comment-100159 Luboš Motl Thu, 04 Sep 2008 18:59:28 +0000 http://dorigo.wordpress.com/?p=1458#comment-100159 I understand that the papers are about similar topics but there are several reasons why I find the recent one more readable: 1) It actually tells us some "average" figures for the masses in the statistical distribution 2) It tells us something about the time needed to detect the preferred scenario(s) by the LHC These might be superficial, easy things but in my optics, they increase the value of the recent paper significantly. Given the similarity of the problems solved in the two papers, it is somewhat puzzling why a more direct comparison is not possible. Cannot each team, for example, rerun their algorithm with the same set of quantities (and the same values and error margins) that the other group used, to check their (two papers') mutual compatibility? To check that the differences are really because of a different set of high-precision observables and due to their different values and not, sorry for this heretical hypothesis, because of serious errors in at least one of the papers? ;-) Best Lubos I understand that the papers are about similar topics but there are several reasons why I find the recent one more readable:

1) It actually tells us some “average” figures for the masses in the statistical distribution
2) It tells us something about the time needed to detect the preferred scenario(s) by the LHC

These might be superficial, easy things but in my optics, they increase the value of the recent paper significantly.

Given the similarity of the problems solved in the two papers, it is somewhat puzzling why a more direct comparison is not possible. Cannot each team, for example, rerun their algorithm with the same set of quantities (and the same values and error margins) that the other group used, to check their (two papers’) mutual compatibility?

To check that the differences are really because of a different set of high-precision observables and due to their different values and not, sorry for this heretical hypothesis, because of serious errors in at least one of the papers? ;-)

Best
Lubos

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