In this review, we first discuss the perspectives concerning a better determination of the proton structure in terms of quarks and gluons at LHC after describing the results coming from HERA and Tevatron. In a second part of the review, we describe the diffractive phenomena at HERA and Tevatron and the consequences for LHC.
部分子分布函数(PDF)是强子对撞机上几乎所有理论预测的不可协商的输入。在这个演讲中,我介绍了PDF测定的全球分析和讨论选定的主题有关最近的相关数据从HERA和Tevatron,然后给出一些LHC的前景。H1和ZEUS截面的组合减少了不确定性,并将成为未来全球PDF分析的重要输入。HERA中重夸克对结构函数贡献的理论描述对LHC的预测有着重要的影响。来自Tevatron Run II的新的W和Z数据提供了重要的PDF约束,但是目前描述来自W -> l nu衰变的轻子电荷不对称性的最新数据存在问题。Tevatron运行II喷气生产数据更喜欢一个较小的高x胶子比以前的运行I数据,这对预测希格斯截面在Tevatron的影响。现在可以一致地计算强子截面的组合“PDF+alpha_S”不确定性,对于LHC的W和Z总截面,其约为2-3%,反映了它们作为测量机器光度的“标准烛光”的潜力。部分子光度函数是研究强子截面性质的有用量。LHC的精确测量将为PDF提供进一步的限制,因为数据在早期运行期间积累。
A review of the current experimental results on searches for Higgs bosons in models beyond the Standard Model is presented. Searches from ATLAS, CMS and LHCb use datasets from Run 1 of the LHC, including 7 and 8 TeV proton-proton collisions. Searches from CDF and D0 use the full or partial 1.96 TeV proton-anti-proton collision datasets from the Tevatron.
Higgs Boson with Large Bottom Yukawa Coupling at Tevatron and LHC
我们研究了Tevatron和LHC探测希格斯玻色子(h)的发现范围,该玻色子(h)是在电弱对称破缺的复合模型或超对称理论中预测的,通过p \bar{p} / p p \to b \bbar h(\to b \bbar)+ X的增强的b夸克汤川耦合。我们的分析表明,在Tevatron Run II或LHC上研究这一过程可以对这些模型提供强有力的约束。
Almost two decades after its discovery at Fermilab's Tevatron collider experiments, the top quark is still under the spotlight due to its connections to some of the most interesting puzzles in the Standard Model. The Tevatron has been shut down two years ago, yet some interesting results are coming out of the CDF and D0 collaborations. The LHC collider at CERN produced two orders of magnitude more top quarks than Tevatron's, thus giving birth to a new era for top quark physics. While the LHC is also down at the time of this writing, many top quark physics results are being extracted out of the…
In these proceedings we summarise the recent studies of exotic hadrons performed at the LHC and Tevatron. The X(3872) production cross section and mass measurements are reported, along with the determination of its quantum numbers, the searches for decays to $\mathrm{p\bar{p}}$, and for partner states in the bottomonium sector. Furthermore, we discuss the Y(4140) and Y(4274) structures, observed by several experiments in the $J/ψϕ$ invariant mass spectrum.
The measurement of a charge asymmetry in t tbar production at LHC constitutes more than an independent confirmation of the forward-backward asymmetry found at Tevatron. Indeed, both measurements together can be used to identify the source of the asymmetry. This is demonstrated for the case of new Z', W' vector bosons and colour-sextet and triplet scalars, exchanged in t, u channels respectively, and a very heavy axigluon in the s channel.
We study contributions of a scalar diquark particle in a color representation of anti-triplet and sextet to the top quark pair production at the Tevatron and the Large hadron collider (LHC). The model can give Forward-Backward (FB) asymmetry at the Tevatron while can avoid the same sign top quark production at the LHC by assuming the top-number conserving diquark couplings. We study compatibility between the large positive FB asymmetry observed at the Tevatron and non-observation of the charge asymmetry at the LHC, by including contributions from the single and pair production of diquarks. We …
We present a systematic comparison of jet predictions at the LHC and the Tevatron, with accuracy up to next-to-next-to-leading order (NNLO). The exact computation at NNLO is completed for the gluons-only channel, so we compare the exact predictions for this channel with an approximate prediction based on threshold resummation, in order to determine the regions where this approximation is reliable at NNLO. The kinematic regions used in this study are identical to the experimental setup used by recently published jet data from the ATLAS and CMS experiments at the LHC, and CDF and D0 experiments …
We consider the top forward-backward (FB) asymmetry at the Tevatron and top charge asymmetry at the LHC within chiral U(1)^\prime models with flavor-dependent U(1)^\prime charges and flavored Higgs fields, which were introduced in the ref. [65]. The models could enhance not only the top forward-backward asymmetry at Tevatron, but also the top charge asymmetry at LHC, without too large same-sign top pair production rates. We identify parameter spaces for the U(1)^\prime gauge boson and (pseudo)scalar Higgs bosons where all the experimental data could be accommodated, including the case with abo…
A sizeable charge asymmetry in top quark pair production has been observed at the Tevatron. The experimental results seem to exceed systematically the Standard Model theory predictions by a significant amount and have triggered a large number of suggestions for 'new physics'. The effect is also visible at the LHC, and preliminary results have already been presented by the ATLAS and CMS collaborations. In this talk, we review the present status of the theoretical predictions, and their comparison with the experimental measurements.
Predictions from the GR@PPA event generator concerning the transverse-momentum ($p_{T}$) spectrum of $Z$ bosons are compared with recent measurements at LHC and Tevatron. The simulation results are in reasonable agreement with the measurements, although marginal discrepancies are observed in high-$p_{T}$ regions. The principal agreements imply that the leading-order simulation with a primitive parton shower based on the leading-logarithmic approximation still provides a reasonable description of the transverse motion of the hard-interaction system in hadron collisions, without the need to intr…
We propose a charged, electrically neutral, and flavour changing Z' model to conciliate the apparent disagreement between the important excess found in the top-antitop Tevatron forward-backward asymmetry and the null -compatible with negative- results found in the LHC charge asymmetry. We show that this model contributes positively to the forward-backward asymmetry, whereas naturally a new cancellation is turned on at the LHC, yielding a null, or even negative, charge asymmetry. We found the region in parameter space that is simultaneously allowed by the stringent Tevatron and LHC observables.…