We summarize some of the work done by the P3 subgroup on Alternative Models and New Ideas. The working group covered a broad range of topics including a constrained Standard Model from an extra dimension, a discussion of recent ideas addressing the strong CP problem, searches for doubly charged higgs bosons in e gamma collisions, and an update on discovery limits for extra neutral gauge bosons at hadron colliders. The breadth of topics reflects the many ideas and approaches to physics beyond the Standard Model.

We report on a measurement of the D+-meson production cross section as a function of transverse momentum (pT) in proton-antiproton (pp) collisions at 1.96 TeV center-of-mass energy, using the full data set collected by the Collider Detector at Fermilab in Tevatron Run II and corresponding to 10 fb-1 of integrated luminosity. We use D+→K-π+π+ decays fully reconstructed in the central rapidity region |y|<1 with transverse momentum down to 1.5 GeV/c, a range previously unexplored in pp collisions. Inelastic pp-scattering events are selected online using minimally biasing requirements followed by an optimized offline selection. The K-π+π+ mass distribution is used to identify the D+ signal, and the D+ transverse impact-parameter distribution is used to separate prompt production, occurring directly in the hard-scattering process, from secondary production from b-hadron decays. We obtain a prompt D+ signal of 2950 candidates corresponding to a total cross section σ(D+,1.5

A measurement of vector boson (V) production in conjunction with a D∗(2010)+ meson is presented. Using a data sample corresponding to 9.7 fb-1 of proton-antiproton collisions at center-of-mass energy s=1.96 TeV produced by the Fermilab Tevatron, we reconstruct V+D∗+ samples with the CDF II detector. The D∗+ is fully reconstructed in the D∗(2010)+→D0(→K-π+)π+ decay mode. This technique is sensitive to the associated production of vector boson plus charm or bottom mesons. We measure the ratio of production cross sections σ(W+D∗)/σ(W)=[1.75±0.13(stat)±0.09(stat)]% and σ(Z+D∗)/σ(Z)=[1.5±0.4(stat)±0.2(stat)]% and perform a differential measurement of dσ(W+D∗)/dpT(D∗). Event properties are utilized to determine the fraction of V+D∗(2010)+ events originating from different production processes. The results are in agreement with the predictions obtained with the pythia program, limiting possible contribution from non-standard-model physics processes.

We measure the forward-backward asymmetry of the production of top-quark and antiquark pairs in proton-antiproton collisions at center-of-mass energy s=1.96 TeV using the full data set collected by the Collider Detector at Fermilab (CDF) in Tevatron Run II corresponding to an integrated luminosity of 9.1 fb-1. The asymmetry is characterized by the rapidity difference between top quarks and antiquarks (Δy) and measured in the final state with two charged leptons (electrons and muons). The inclusive asymmetry, corrected to the entire phase space at parton level, is measured to be AFBtt=0.12±0.13, consistent with the expectations from the standard model (SM) and previous CDF results in the final state with a single charged lepton. The combination of the CDF measurements of the inclusive AFBtt in both final states yields AFBtt=0.160±0.045, which is consistent with the SM predictions. We also measure the differential asymmetry as a function of Δy. A linear fit to AFBtt(|Δy|), assuming zero asymmetry at Δy=0, yields a slope of α=0.14±0.15, consistent with the SM prediction and the previous CDF determination in the final state with a single charged lepton. The combined slope of AFBtt(|Δy|) in the two final states is α=0.227±0.057, which is 2.0σ larger than the SM prediction.

An updated measurement of the single top quark production cross section is presented using the full data set collected by the Collider Detector at Fermilab (CDF), corresponding to 9.5 fb-1 of integrated luminosity from proton-antiproton collisions at 1.96 TeV center-of-mass energy. The events selected contain an imbalance in the total transverse momentum, jets identified as containing b quarks, and no identified leptons. The sum of the s- and t-channel single top quark cross sections is measured to be 3.53-1.16+1.25 pb and a lower limit on the magnitude of the top-to-bottom quark coupling, |Vtb| of 0.63, is obtained at the 95% credibility level. These measurements are combined with previously reported CDF results obtained from events with an imbalance in total transverse momentum, jets identified as originating from b quarks, and one identified lepton. The combined cross section is measured to be 3.02-0.48+0.49 pb and a lower limit on |Vtb| of 0.84 is obtained at the 95% credibility level.

The Collider Detector at Fermilab collected a unique sample of jets originating from bottom-quark fragmentation (b-jets) by selecting online proton-antiproton (pp̄) collisions with a vertex displaced from the pp̄ interaction point, consistent with the decay of a bottom-quark hadron. This data set, collected at a center-of-mass energy of 1.96 TeV, and corresponding to an integrated luminosity of 5.4 fb-1, is used to measure the Z-boson production cross section times branching ratio into bb̄. The number of Z→bb̄ events is determined by fitting the dijet-mass distribution, while constraining the dominant b-jet background, originating from QCD multijet events, with data. The result, σ(pp̄→Z)×B(Z→bb̄)=1.11±0.08(stat)±0.14(syst) nb, is the most precise measurement of this process, and is consistent with the standard-model prediction. The data set is also used to search for Higgs-boson production. No significant signal is expected in our data and the first upper limit on the cross section for the inclusive pp̄→H→bb̄ process at s=1.96 TeV is set, corresponding to 33 times the expected standard-model cross section, or σ=40.6 pb, at the 95% confidence level.

We report a measurement of the forward-backward asymmetry, AFB, in bb pairs produced in proton-antiproton collisions and identified by muons from semileptonic b-hadron decays. The event sample is collected at a center-of-mass energy of s=1.96 TeV with the CDF II detector and corresponds to 6.9 fb-1 of integrated luminosity. We obtain an integrated asymmetry of AFB(bb)=(1.2±0.7)% at the particle level for b-quark pairs with invariant mass, mbb, down to 40 GeV/c2 and measure the dependence of AFB(bb) on mbb. The results are compatible with expectations from the standard model.

At the Fermilab Tevatron proton-antiproton (pp) collider, Drell-Yan lepton pairs are produced in the process pp→e+e-+X through an intermediate γ∗/Z boson. The forward-backward asymmetry in the polar-angle distribution of the e- as a function of the e+e - pair mass is used to obtain sin2θefflept, the effective leptonic determination of the electroweak-mixing parameter sin2θW. The measurement sample, recorded by the Collider Detector at Fermilab (CDF), corresponds to 9.4 fb-1 of integrated luminosity from pp collisions at a center-of-momentum energy of 1.96 TeV, and is the full CDF Run II data set. The value of sin2θefflept is found to be 0.23248±0.00053. The combination with the previous CDF measurement based on μ+μ- pairs yields sin2θefflept=0.23221±0.00046. This result, when interpreted within the specified context of the standard model assuming sin2θW=1-MW2/MZ2 and that the W- and Z-boson masses are on-shell, yields sin2θW=0.22400±0.00045, or equivalently a W-boson mass of 80.328±0.024 GeV/c2.

We study charged particle production (pT>0.5 GeV/c, |η|<0.8) in proton-antiproton collisions at total center-of-mass energies s=300 GeV, 900 GeV, and 1.96 TeV. We use the direction of the charged particle with the largest transverse momentum in each event to define three regions of η-φ space: "toward", "away", and "transverse." The average number and the average scalar pT sum of charged particles in the transverse region are sensitive to the modeling of the "underlying event." The transverse region is divided into a MAX and MIN transverse region, which helps separate the "hard component" (initial and final-state radiation) from the "beam-beam remnant" and multiple parton interaction components of the scattering. The center-of-mass energy dependence of the various components of the event is studied in detail. The data presented here can be used to constrain and improve QCD Monte Carlo models, resulting in more precise predictions at the LHC energies of 13 and 14 TeV.

We present a measurement of the total WW and WZ production cross sections in pp collision at s=1.96 TeV, in a final state consistent with leptonic W boson decay and jets originating from heavy-flavor quarks from either a W or a Z boson decay. This analysis uses the full data set collected with the CDF II detector during Run II of the Tevatron collider, corresponding to an integrated luminosity of 9.4 fb-1. An analysis of the dijet mass spectrum provides 3.7σ evidence of the summed production processes of either WW or WZ bosons with a measured total cross section of σWW+WZ=13.7±3.9 pb. Independent measurements of the WW and WZ production cross sections are allowed by the different heavy-flavor decay patterns of the W and Z bosons and by the analysis of secondary-decay vertices reconstructed within heavy-flavor jets. The productions of WW and of WZ dibosons are independently seen with significances of 2.9σ and 2.1σ, respectively, with total cross sections of σWW=9.4±4.2 pb and σWZ=3.7-2.2+2.5 pb. The measurements are consistent with standard-model predictions.