Student Presentations at FAPPS09

Standard Model

Proposed by Vanina Ruhlmann-Kleider.

• Measurement of the standard model parameters from a study of W and Z bosons, UA2 collaboration, Phys. Lett. B186 (1987) 440

Tests of the standard model by one of the experiments which first observed the weak intermediate bosons in the 80's at CERN. This is much less precise than what was done in the next generation of experiments (LEP and SLC) but is interesting to read for historical reasons. Note also that the measurement of the W decay product asymmetry presented in this paper was not repeated afterwards.

• A precise determination of the electroweak mixing angle from semileptonic neutrino scattering, the CHARM collaboration, Z. Phys. C36 (1987) 611.

Determination of the electroweak mixing angle from neutrino scattering before the advent of LEP/SLC experiments. At that time, neutrino scattering offered the most precise method to measure sin2(theta_w). Comparing their measurement with that deduced from W and Z masses measured at hadron colliders, this paper concluded that standard model calculations had to be pushed beyond first order to reconcile the different experiments. The aim of LEP/SLC experiments was to test these extended calculations with great precision.

• A combined analysis of the hadronic and leptonic decays of the Z0, OPAL collaboration, Phys. Lett. B240 (1990) 497.

Early derivation of the number of neutrino species from measurements of the Z0 line shape from the first year of data taking at LEP. This is the first constraint that LEP experiments placed on the standard model after only one year of running and a modest amount of Z0 events collected. The precision on the number of neutrino species improved a lot afterwards when millions of Z decays were recorded but the conclusion remained identical.

• Updated parameters of the Z0 resonance from combined preliminary data of the LEP experiments, the LEP collaborations, CERN-PPE/93-157.

Combination of all four LEP experiment measurements on the Z0 resonance that gave the first indirect constraint on the top quark mass before its discovery at the Tevatron. More technical that the other papers (less experimental details) this publication explains how the standard model can be tested with precise electroweak measurements.

• Cross-sections and leptonic forward-backward asymmetries from the Z0 running of LEP, DELPHI collaboration, Eur. Phys. J C16 (2000) 371.

Summary of all Z cross-section and Z decay angular asymmetry measurements performed at LEP1 by one of the LEP experiments. All measurements reported here are final. They are used to test the standard model and derive indirect constraints on various standard model parameters (number of neutrino species, top mass, strong interaction coupling constant...). This is an example of constraints that can be placed on the standard model with the full statistics of LEP1. By combining more measurements from the four LEP experiments as well as from other experiments the standard model can be tested even more precisely.

• First run II measurement of the W boson, the CDF collaboration, Phys. Rev. D77 (2008) 112001.

First measurement of the W mass from run II data at the Tevatron. Experimental details are given about the event selection and the method to ensure a precise measurement of the W mass, which is an key ingredient of the standard model tests.

• Measurement of the top quark mass in the lepton+jets channel using the matrix element method on 3.6fb-1 of D0 run II data, the D0 collaboration, D0 note 5877-CONF.

One of the most precise measurements of the top quark mass at the Tevatron. Describes the event selection, the (not trivial) method used to derive the mass and the calibration of the method. The precise value of the top mass is a key ingredient of the standard model tests.

B physics

Proposed by Stephane T'Jampens.

• The measurement of sin2beta at BABAR and Belle (Phys.Rev.Lett.87:091801,2001, Phys.Rev.Lett.87:091802,2001)

To be linked with the 2008 Nobel prize. The papers to be read are the 2001 papers that established CP Violation in B-meson system in agreement with the KM mechanism. Also included are the PRD papers to have more details (Phys.Rev.D66:032003,2002, Phys.Rev.D66:071102,2002).

Proposed by Youngjoon Kwon.

• Study of electroweak penguin decays of B mesons from B-factory experiment (Phys. Rev. D 69, 112001, 2004, Phys. Rev. Lett. 91, 261601, 2003 and axXiv:0904.0770v2)

Charm Physics

Proposed by Changzheng Yuan.

• Study of psi'-->pi+pi-J/psi and search for other states decay into pi+pi-J/psi, with J/psi-->lepton pair, at BES (Phys.Rev.D62:032002,2000), CLEO (Phys.Rev.D78:011102,2008) and Belle (Phys.Rev.Lett.99:182004,2007)

Rare KL decay

Proposed by Takeshi Komatsubara

• CP-violating decay KL->pi0nunubar

Main reference is Phys. Rev. D39 (1989), 3322. To get more on the theoretical discussions beyond the Standard Model, see also Phys. Lett. B398 (197), 163. Experimental searches are presented in Phys. Rev. D61 (2000), 072006 and Phys. Rev. Lett. 100 (2008), 201802.

-- LydiaRoos - 21 Oct 2009