Friday, June 16, 2006

Hep-ph papers on Friday

There are seven papers on hep-ph today, so it may be interesting to look at them to have some idea about the representation of different topics among the phenomenologists. There are no SUSY papers on hep-ph today which might be correlated with the fact that the conference SUSY '06 is just underway.

Erhan Iltan studies phenomenology of models with extra dimensions. He has two large extra dimensions and imagines that the fermions are localized in one of them and the second Higgs field that is being added is localized in another dimension; this could actually bear some resemblance to the intersecting braneworlds. The exotic effects he or she wants to calculate are the electric dipole moments and the flavor lepton number violating decays. The paper has one of the longest titles in the history of science. ;-)

Jonathan Rosner reviews the recent progress in the precise measurements of spectra of hadrons, especially hadrons with heavy quarks, including heavy quark-antiquark bound states, but also glueballs and hybrids.

The UTfit collaboration offers a lot of nice colorful plots indicating the results of many experiments from the realm of B-physics i.e. physics of the bottom quark and its bound states that is the key for determining the precise values of the CKM matrix and the apparent fact that this matrix is the only source of CP violation. Various quantities for different quarks must satisfy certain constraints if the CKM description is accurate, and the authors check this "unitarity triangle fit", as measured at Fermilab, with the help of lattice QCD.

Lorenzo Magnea talks about angularities and other shapes. This is the part of QCD - soft gluon resummations etc. - that is relevant for many processes to be seen at the LHC collider. He derives a scaling rule using purely perturbative QCD methods. It's the kind of paper that Nina Byers would definitely need to consider in her encyclopedia of LHC Standard Model phenomenology.

White, Peschanski, and Thorne also study complex physics of strong interactions. Most of their calculations look like Feynman loop diagrams of cross sections for virtual photons and gluons (at the tree level, gluons don't interact with photons!) in which the loops are created from massive quarks. It is new work following the Soviet BFKL equation from the 1970s that is relevant for a full description of the deep inelastic scattering.

Gao, Zhang, and Chao calculate the decays of a charmed particle (Upsilon) to light quarks. They consider not only the color-singlet initial state but also a color-octet state. For color singlets, they find that the branching ration of Upsilon decaying into "photon quark anti-quark" is about 0.1% while for the octet the ratio is much higher, which could be relevant for verification of the color octet mechanism proposed in non-relativistic QCD.

Alejandro Rivero tries to find the approximate value of the Weinberg's weak mixing angle (in his case, 0.223 for the squared sine) in the Old Testament. Finally he finds the number in a 1924 timecapsule. There are also words such as "supersymmetry" or "Regge" in the paper. But sorry, Leucipo, I think that the content actually has nothing to do with physics, and it is numerology with the same likelihood of success as the probability that one finds a pound of gold in a generic restroom when one looks sufficiently deeply. ;-)


  1. :-DDDDD

    So now you comment on hep-ph too!! (and from the final remark, you so it while looking the film "Paint Your Wagon", where a young Clint Eastwood mines gold out of the floor of restrooms)

    Dont worry anyway, it is mostly a remark I considered worthwhile to annotate. Why? Because it originated in a physics model (this "1924" relativistic orbit) and the algebraic expressions are simple enough to appear when doing more serious model building. The "super-" is naive, yep, just done to stress that the mass terms are to be evaluated for s=1 and s=1/2. The more numerological fact is the amusing fact that the formula also hits the square mass of the higgs field, with the adequate negative sign.

    Of course the expresions on masses are nonsense if one thinks that such relationships are to be stablished at GUT level and then run down via renormalisatio group. I am beginning to believe this is not so, because the mass of the top is amusingly coincidental with the electroweak vacuum (as mentioned in the paper).

  2. hep-th/0606142

    It's about meritorious evidence of the Sen’s third conjecture: there are no on-shell perturbative excitations of the tachyon vacuum in OSFT.

  3. I have always been wondering whether there is some maximal length cutoff on arxiv-titles. I should try that...

  4. I will be travelling tomorrow so I will not know of the news of the Higgs. But if roumours are confirmed, someone should convince Hans to write a paper more readable than mine.

    Now, let me remember that this paper, taking as reference mass input the Z0 mass, was able to give the mass of W and two extras mases; one was at the typical value of top, or electroweak vacuum depending normalization. The other mass I didn't like, and in fact I did some efforts (in physicsforums, mainly) to retort it down to 115 or 113 GeV. But well, you can go again to the paper, go to formula 9, and read:

    122.384 GeV

    Five years later, the paper is hard to follow even to me; it is fortunate that all the discussion is archived in physicsforums.