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A chat with Arkani-Hamed at CERN December 9, 2008

Posted by dorigo in physics.

Tonight I am happy to report that my usual bluntness and speak-your-mind attitude is not per se an attribute which drives people away and creates grudges and enmity. I am what I am, but I am of course worried when I see that what I am driven to write in this blog pisses people off -especially when it happens with esteemed colleagues.

If I look back a couple of months, I can spot at least three notable “incidents”.

The first incident is my explicit disbelief at the originality of the paper by Arkani-Hamed, Weiner et al., which suggested lepton jets as signatures of new physics to be exploited at the LHC. This caused arguments -better call them exchanges- with Neal Weiner and with Nima Arkani-Hamed (see here for the original epistolary). Nima, in particular, had a remarkable incipit in his comment to my blog post:

As most of my friends and colleagues know, I have a very dim view of the physics blogosphere, and avoid interacting with it. However, your statements about me and my collaborators in connection with the recent CDF anomaly quite clearly crossed a line, and I feel compelled to respond. In doing so I am adopting an attitude Howard Georgi once described when dealing with non-perturbative QCD effects in heavy quark effective theory: once I am finished dealing with the brown muck, I will wash my hands.

[The only reason I quote this here is in connection with what my meeting with him today, which I report below.]

The second incident came with  Matt Strassler’s preprint on “flesh and blood with Multi-muons”, which prompted a post where I expressed some concerns on the way the author list of the recent multi-muon paper by CDF was being used as a notitia criminis.

The third was the trap into which poor Lubos Motl fell head first, when I asked him to justify a wrong cross section estimate in Strassler’s paper (admittedly an error caused by the cryptic way the CDF paper is written, but Lubos would have had several occasions to understand he was fighting a lost cause, if his huge ego had not hindered him), which caused an endless exchange, only stopped by my request for an official apology -which ultimately rang a bell and forced Lubos to ask to independent sources, after which he came back to indeed apologize.

Now, this is not an assault blog. This is a site where I make a honest attempt at making particle physics accessible to whomever has ears to listen. However, it is of course true that things such as those listed above “spice things up” a bit. Indeed, I can see distinct peaks in the number of daily visits to this blog which are presumably due to the Hamed/Weiner, Strassler, and Motl affairs. Ultimately, as much as we like to look at them with from other perspectives, blogs are a form of journalism, so they have the tendency to drift toward the malpractice of “building news” around facts. I apologize for that: it does happen here too, occasionally.

In any case, what I really want to avoid is to make things hard for myself as a physicist by running this site. My job is to study physics, but this involves having positive professional relationships with colleagues around the world, which in turn this entails avoiding to get people upset with what I write.

Now, yesterday I had a constructive e-mail exchange with Matt Strassler. He was extremely polite and showed he was not upset about my post on his paper, and this after all was a relief. But most of all, I was happy today with my interaction with Nima Arkani-Hamed.

Nima is at CERN, and today he gave a talk at an Exotics meeting of CMS, where he discussed new physics scenarios involving “hidden valleys” of particles with a small, but not negligible, coupling to Standard Model particles. I have taken a transcript of his very interesting talk, but I am presently waiting for an authorization by the management of CMS to paste  it here-technically, anything that is discussed at a CMS internal meeting cannot be publicized in blogs.

I wanted to intercept Nima after his talk, but in the crowd of the meeting I was prevented from doing so. I gave up, but I was in for a surprise. While having dinner tonight at the CERN canteen I had the luck of finding Nima seated in plain view, in a semi-desert dining room, and only weakly interacting with his guest. So I took my chance. I walked up to his table, and offered him my hand -which he shook unhesitantly- while I uncorked the pre-cooked-up line, “Hello Nima, I’m Muck. Brown Muck“.

It took him a while to understand -the incident in my blog is a month old by now, and he obviously did not know my face. But he was very well-mannered and all smiles, and we entertained ourselves with a discussion of the CDF signal, the details of impact parameters and where they may come from, cross section issues, and other considerations about the way particle physics experiments usually lock up invaluable information which theorists such as him would be very happy to receive.

So, at the price of having to eat the second half of my dinner quite cold, I had the pleasure of meeting Nima Arkani-Hamed in person, of finding out he was really not concerned with our internet exchange, and of having a stimulating discussion with him. This enforces my point that intelligent people do have a sense of humor, and generally are hard to get upset. Next time I will try harder!

Oh, and -about the issue: did talking with Nima change my views on the “original” nature of the preprint he wrote with Weiner et al. ? Well. I like to say only stupid people never change their mind. I must say that talking to him in person, looking at him in his eyes, listening to his talk this morning – all this had some effect. I still have my own ideas, but I am not so sure about their correctness any more, so I will leave it at that. And besides: it’s all background. Well, 99% sure. Who knows…


1. Mandeep - December 9, 2008

T- i’m glad you kind of ‘made up’ with Nima — i didn’t follow all the back and forth, but i’ve just known him as a really great guy (he was a member of my thesis committee for a time), and would’ve been surprised if he’s doing really ‘bad things’. seems you feel better about him, and i’m happy to hear this, and that you’re getting it out publically too — your blog is def. fairly widely read, and i’m sure has ripples pretty far beyond what you or others might think at times.

Anyway – looking someone right in the eyes and talking can clarify a lot and connect people in a real heart to heart way that email, or even talking on the phone, can’t always do.

So — good deal! :>


2. Henry Deith - December 10, 2008

A nice post, Tommaso, we look forward to reading the transcript of Nima’s talk should CMS permit.

After reading your last paragraph, however, I cannot but help but noticing the similarity to a quote by a certain lame-duck president: “I looked the man in the eye. I found him to be very straightforward and trustworthy. We had a very good dialogue. I was able to get a sense of his soul.”

3. Andrea Giammanco - December 11, 2008

I’m also eager to read the transcript!
I had not the opportunity to be at CERN this week, so I connected to that meeting via EVO, just to be disappointed in discovering that they were not able to broadcast the screen where he was showing his slides (hand-made, I guess, since they were not even in the agenda).
Listening to his voice without seeing the images was not very informative, so I gave up.

4. Arkani-Hamed: “Dark Forces, Smoking Guns, and Lepton Jets at the LHC” « A Quantum Diaries Survivor - December 11, 2008

[…] revealed it, markers were found, and eventually things were set for his talk. However, people like Andrea, who counted on following the talk remotely on Evo, were rather turned off by the choice of […]

5. dorigo - December 11, 2008

Henry, you are right. A quote to dump in the trashbin of history, along with its owner.


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