Future Colliders

Research group

Research theme

Sub department

About

Combined HERA deep inelastic scattering data and NLO QCD fits

Conference Proceedings - New Trends in HERA Physics 2008 (2008)

Abstract:

Previously published data on inclusive neutral and charged current e +p and e-p deep inelastic scattering from HERA have been combined. The new, model-independent method of combining the measured cross sections takes full account of correlated systematics in a coherent way, leading to significantly reduced uncertainties in the combined measurement across the (x;Q2) plane. The combined cross section data have been used as the sole input for a new next-to-leading order QCD fit to extract the parton distribution functions (PDFs) of the proton. The PDFs extracted have greatly reduced experimental uncertainties, compared to separate QCD analyses on data from H1 and ZEUS. Model uncertainties, including those arising from the parameterisation dependence, have also been carefully considered. The resulting HERA PDFs have impressive precision.

First measurement of the fraction of top-quark pair production through gluon-gluon fusion

Physical Review D Particles Fields Gravitation and Cosmology 78:11 (2008)

Authors:

T Aaltonen, J Adelman, T Akimoto, MG Albrow, B Álvarez González, S Amerio, D Amidei, A Anastassov, A Annovi, J Antos, M Aoki, G Apollinari, A Apresyan, T Arisawa, A Artikov, W Ashmanskas, A Attal, A Aurisano, F Azfar, P Azzi-Bacchetta, P Azzurri, N Bacchetta, W Badgett, A Barbaro-Galtieri, VE Barnes, BA Barnett, S Baroiant, V Bartsch, G Bauer, PH Beauchemin, F Bedeschi, P Bednar, S Behari, G Bellettini, J Bellinger, A Belloni, D Benjamin, A Beretvas, J Beringer, T Berry, A Bhatti, M Binkley, D Bisello, I Bizjak, RE Blair, C Blocker, B Blumenfeld, A Bocci, A Bodek, V Boisvert, G Bolla, A Bolshov, D Bortoletto, J Boudreau, A Boveia, B Brau, A Bridgeman, L Brigliadori, C Bromberg, E Brubaker, J Budagov, HS Budd, S Budd, K Burkett, G Busetto, P Bussey, A Buzatu, KL Byrum, S Cabrera, M Campanelli, M Campbell, F Canelli, A Canepa, D Carlsmith, R Carosi, S Carrillo, S Carron, B Casal, M Casarsa, A Castro, P Catastini, D Cauz, M Cavalli-Sforza, A Cerri, L Cerrito, SH Chang, YC Chen, M Chertok, G Chiarelli, G Chlachidze, F Chlebana, K Cho, D Chokheli, JP Chou, G Choudalakis, SH Chuang, K Chung, WH Chung, YS Chung, CI Ciobanu

Abstract:

We present the first measurement of σ(gg→tt̄)/ σ(pp̄→tt̄). We use 0.96fb-1 of s=1.96TeV pp̄ collision data recorded with the CDF II detector at Fermilab. Using charged particles with low transverse momentum in tt̄ events, we find σ(gg→ tt̄)/σ(pp̄→tt̄)=0.07±0.14(stat)±0. 07(syst), corresponding to a 95% confidence level upper limit of 0.33, in agreement with the standard model next-to-leading-order prediction of 0.15±0.05. © 2008 The American Physical Society.

ILC main linac alignment simulations using conventional techniques and the rapid tunnel reference survey model (RTRSM)

Electronic Proceedings of the International Linear Collider Workshop 2008, LCWS 2008 and ILC 2008 (2008)

Authors:

J Dale, A Reichold

Abstract:

Alignment of the ILC main linac will be more critical than for any currently existing accelerators due to its long length and the ultra low emittance required. There are several techniques for measuring the ILC reference network; in this report conventional methods for measuring the network and aligning the main linac are simulated. Dispersion Matched Steering (DMS) is applied to the simulated accelerators to determine their final emittance. Simulations and reconstructions of the ILC reference network usually require very resource intensive programs, the RTRSM has been developed to rapidly generate networks with the required statistical properties. The RTRSM is discussed in this report and some problems are demonstrated.

The ATLAS experiment at the CERN large hadron collider

Journal of Instrumentation 3:8 (2008)

Authors:

G Aad, E Abat, J Abdallah, AA Abdelalim, A Abdesselam, O Abdinov, BA Abi, M Abolins, H Abramowicz, E Acerbi, BS Acharya, R Achenbach, M Ackers, DL Adams, F Adamyan, TN Addy, M Aderholz, C Adorisio, P Adragna, M Aharrouche, SP Ahlen, F Ahles, A Ahmad, H Ahmed, G Aielli, PF Åkesson, TPA Akesson, AV Akimov, SM Alam, J Albert, S Albrand, M Aleksa, IN Aleksandrov, M Aleppo, F Alessandria, C Alexa, G Alexander, T Alexopoulos, G Alimonti, M Aliyev, PP Allport, SE Allwood-Spiers, A Aloisio, J Alonso, R Alves, MG Alviggi, K Amako, P Amaral, SP Amaral, G Ambrosini, G Ambrosio, C Amelung, VV Ammosov, A Amorim, N Amram, C Anastopoulos, B Anderson, KJ Anderson, EC Anderssen, A Andreazza, V Andrei, L Andricek, ML Andrieux, XS Anduaga, F Anghinolfi, A Antonaki, M Antonelli, S Antonelli, R Apsimon, G Arabidze, I Aracena, Y Arai, ATH Arce, JP Archambault, JF Arguin, E Arik, M Arik, KE Arms, SR Armstrong, M Arnaud, C Arnault, A Artamonov, S Asai, S Ask, B Åsman, D Asner, L Asquith, K Assamagan, A Astbury, B Athar, T Atkinson, B Aubert, B Auerbach, E Auge, K Augsten, VM Aulchenko, N Austin, G Avolio, R Avramidou, A Axen

Measurement of the kT Distribution of Particles in Jets Produced in ppbar Collisions at s**(1/2)=1.96$-TeV

ArXiv 0811.2820 (2008)

Authors:

CDF Collaboration, T Aaltonen