2006 Topcites

Every year the people running SPIRES put together a list of the most heavily cited papers in their database. I’ve discussed here in the past the listings for 2003, 2004 and 2005. Up until 2003 these appeared with a discussion by Michael Peskin of many of the papers on the list and their significance, but he hasn’t done this for the past couple years. This year, instead of waiting for the SLAC people to put together the list, I decided to generate one myself. I’m not enough of an expert with SPIRES to get it to just give me the list for 2006, but it was an interesting exercise to go through the lists generated by various searches just using their “topcite 50+, topcite 100+, etc…” feature, together with restrictions on dates. I think I was able to compile a complete list of papers with 150 or more citations, and post-1990 papers with 100-150. I was just looking at papers in particle theory (hep-th, hep-ph, hep-lat), not experimental (hep-ex) papers or astrophysics (astro-ph) papers, and was not counting survey articles. I’ve put the full list on a separate web-page, Most Heavily Cited Theoretical Particle Physics Papers 2006.

There are of course lots of caveats about any conclusions drawn from counting citations, but these numbers do give some solid data about what is going on these days in particle theory research. Two topics from nearly a decade ago continue to dominate these citation counts: AdS/CFT and brane-world models. By far the most heavily cited paper is the original 1997 one by Maldacena (546 citations), and the number of such citations has actually increased significantly over the number in 2004 (451) and 2005 (436). Research into AdS/CFT heavily dominates current particle theory research, but, remarkably, this research has not led to any recent heavily-cited papers on the subject. After a flurry of activity in 1998-2000, the only 21st century paper on the topic with over 100 citations in 2006 is the 2002 paper on pp-wave backgrounds by Berenstein et. al.

Overall, the list provides a very depressing view of the first six years of 21st century theoretical particle physics, with only eight post-2000 papers getting over 100 citations. These break up neatly into 4 hep-th string theory papers and 4 hep-ph phenomenology papers. Besides the 2002 pp-wave paper (hep-th/0202021) the other three string theory papers are all about the landscape, with the KKLT paper (hep-th/0301240) getting by far the most citations (238), followed by hep-th/0105097 (Giddings, Kachru, Polchinski) with 150, and Susskind’s hep-th/0302219 (“The Anthropic landscape of string theory”) with 109.

The heavily cited phenomenology papers are mostly compilations of theoretical fits to experimental data: hep-ph/0201195 (parton distributions, 193 citations), hep-ph/0405172 (neutrino oscillations, 133 citations), hep-ph/0406184 (CKM matrix, 118) and hep-ph/0506083 (neutrino mass matrix, 103 citations).

While getting this list together, I also accumulated some other data, including lists of recent papers with citation counts in the range of 50-100, and will try and put this together and write about it sometime soon.

Some other data one might want to take a look at is the arXiv monthly count of submissions (I found out about this from a posting at physicsforums). It shows the number of HEP submissions growing until about 2002, more or less flat since then, although each of the last two years have shown slight declines.

I’ll avoid the temptation to make extensive editorial comment on the meaning of these numbers, but I find it hard to believe that anyone could claim that they reflect a healthy field. The domination of non-phenomenological particle theory research by landscape studies is especially disturbing.