共查询到20条相似文献,搜索用时 15 毫秒
1.
We propose an improved method for hadron-collider mass determination of new states that decay to a massive, long-lived state like the LSP in the MSSM. We focus on pair-produced new states which undergo three-body decay to a pair of visible particles and the new invisible long-lived state. Our approach is to construct a kinematic quantity which enforces all known physical constraints on the system. The distribution of this quantity calculated for the observed events has an endpoint that determines the mass of the new states. However we find it much more efficient to determine the masses by fitting to the entire distribution and not just the end point. We consider the application of the method at the LHC for various models and demonstrate that the method can determine the masses within about 6 GeV using only 250 events. This implies the method is viable even for relatively rare processes at the LHC such as neutralino pair production. 相似文献
2.
Ignatios Antoniadis Alexey Boyarsky Sam Espahbodi Oleg Ruchayskiy James D. Wells 《Nuclear Physics B》2010,824(1-2):296-313
Many extensions of the Standard Model (SM) predict new neutral vector bosons at energies accessible by the Large Hadron Collider (LHC). We study an extension of the SM with new chiral fermions subject to non-trivial anomaly cancellations. If the new fermions have SM charges, but are too heavy to be created at LHC, and the SM fermions are not charged under the extra gauge field, one would expect that this new sector remains completely invisible at LHC. We show, however, that a non-trivial anomaly cancellation between the new heavy fermions may give rise to observable effects in the gauge boson sector that can be seen at the LHC and distinguished from backgrounds. 相似文献
3.
This article reviews recent measurements of the properties of the standard model (SM) Higgs boson using data recorded with the CMS detector at the LHC: its mass, width and couplings to other SM particles. We also summarise highlights from searches for new physical phenomena in the Higgs sector as they are proposed in many extensions of the SM: flavour violating and invisible decay modes, resonances decaying into Higgs bosons and searches for additional Higgs bosons. 相似文献
4.
W. J. Stirling E. Vryonidou J. D. Wells 《The European Physical Journal C - Particles and Fields》2011,71(5):1642
We compute transplanckian parton scattering in flat extra-dimensional theories at the LHC and at the recently discussed high-energy
upgrade (HE LHC). We report new leading-order calculations of the QCD background. We apply appropriate cuts to satisfy the
necessary conditions for the eikonal approximation to be valid while at the same time maximising the signal to background
ratio at LHC energies. We study the computability of the eikonal signal and consider the effect of a possible 33 TeV high-energy
upgrade to the LHC, which serves to extend the calculable region and to enhance the signal to background ratio. 相似文献
5.
The little Higgs model provides an alternative to traditional candidates for new physics at the TeV scale. The new heavy gauge bosons predicted by this model should be observable at the CERN Large Hadron Collider (LHC). We discuss how the LHC experiments could test the little Higgs model by studying the production and decay of these particles. 相似文献
6.
7.
A. De Roeck J. Ellis C. Grojean S. Heinemeyer K. Jakobs G. Weiglein J. Wells G. Azuelos S. Dawson B. Gripaios T. Han J. Hewett M. Lancaster C. Mariotti F. Moortgat G. Moortgat-Pick G. Polesello S. Riemann M. Schumacher K. Assamagan P. Bechtle M. Carena G. Chachamis K. F. Chen S. De Curtis K. Desch M. Dittmar H. Dreiner M. Dührssen B. Foster M. T. Frandsen A. Giammanco R. Godbole S. Gopalakrishna P. Govoni J. Gunion W. Hollik W. S. Hou G. Isidori A. Juste J. Kalinowski A. Korytov E. Kou S. Kraml M. Krawczyk A. Martin D. Milstead V. Morton-Thurtle K. Moenig B. Mele E. Ozcan M. Pieri T. Plehn L. Reina E. Richter-Was T. Rizzo K. Rolbiecki F. Sannino M. Schram J. Smillie S. Sultansoy J. Tattersall P. Uwer B. Webber P. Wienemann 《The European Physical Journal C - Particles and Fields》2010,66(3-4):525-583
Discoveries at the LHC will soon set the physics agenda for future colliders. This report of a CERN Theory Institute includes the summaries of Working Groups that reviewed the physics goals and prospects of LHC running with 10 to 300 fb?1 of integrated luminosity, of the proposed sLHC luminosity upgrade, of the ILC, of CLIC, of the LHeC and of a muon collider. The four Working Groups considered possible scenarios for the first 10 fb?1 of data at the LHC in which (i) a state with properties that are compatible with a Higgs boson is discovered, (ii) no such state is discovered either because the Higgs properties are such that it is difficult to detect or because no Higgs boson exists, (iii) a missing-energy signal beyond the Standard Model is discovered as in some supersymmetric models, and (iv) some other exotic signature of new physics is discovered. In the contexts of these scenarios, the Working Groups reviewed the capabilities of the future colliders to study in more detail whatever new physics may be discovered by the LHC. Their reports provide the particle physics community with some tools for reviewing the scientific priorities for future colliders after the LHC produces its first harvest of new physics from multi-TeV collisions. 相似文献
8.
Jun-Quan Tao M. Aamir Shahzad Si-Jing Zhang Chu Wang Yu-Qiao Shen Guo-Ming Chen He-Sheng Chen S. Gascon-Shotkin M. Lethuillier L. Finco C. Camen 《中国物理C(英文版)》2018,42(10):103107-103107
Following the discovery of the Higgs boson with a mass of approximately 125 Ge V at the LHC, many studies have been performed from both the theoretical and experimental viewpoints to search for a new Higgs Boson that is lighter than 125 Ge V. We explore the possibility of constraining a lighter neutral scalar Higgs boson h_1 and a lighter pseudo-scalar Higgs boson a_1 in the Next-to-Minimal Supersymmetric Standard Model by restricting the next-to-lightest scalar Higgs boson h_2 to be the one observed at the LHC after applying the phenomenological constraints and those from experimental measurements. Such lighter particles are not yet completely excluded by the latest results of the search for a lighter Higgs boson in the diphoton decay channel from LHC data. Our results show that some new constraints on the Next-to-Minimal Supersymmetric Standard Model could be obtained for a lighter scalar Higgs boson at the LHC if such a search is performed by experimental collaborations and more data. The potentials of discovery for other interesting decay channels of such a lighter neutral scalar or pseudo-scalar particle are also discussed. 相似文献
9.
《Comptes Rendus Physique》2015,16(4):407-423
In this review, we present highlight results of the first three years of the LHC running on searches for new physics beyond the Standard Model. The excellent performance of the LHC machine and detectors has provided a large, high-quality dataset, mainly proton–proton interactions at a centre of mass energy of 7 TeV (collected in 2010 and 2011) and 8 TeV (collected in 2012). This allowed the experiments to test the Standard Model at the highest available energy and to search for new phenomena in a considerably enlarged phase space compared to previous colliders. 相似文献
10.
V. M. Zhabitsky 《Physics of Particles and Nuclei Letters》2006,3(1):S58-S61
Transverse feedback systems for suppression of transverse coherent beam oscillations are used in modern synchrotrons for preventing the development of transverse instabilities and damping residual beam oscillations after injection. Information on damper systems for the Large Hadron Collider (LHC; CERN, Geneva) and the accelerator complex FAIR (GSI, Darmstadt) is presented. The project for the LHC is being performed at the Laboratory of Particle Physics of the Joint Institute for Nuclear Research in collaboration with CERN. The information concerning the state of the project and the plans of its completion at the LHC is given. The results of the first design activity on transverse damping systems at the SIS100 and SIS300 synchrotrons, to be created in the framework of the new international project FAIR, are presented. 相似文献
11.
Important goals of BNL RHIC and CERN LHC experiments with ion beams include the creation and study of new forms of matter, such as the quark gluon plasma. Heavy quark production and attenuation provide unique tomographic probes of that matter. We predict the suppression pattern of open charm and beauty in Au+Au collisions at RHIC and LHC energies based on the DGLV formalism of radiative energy loss. A cancellation between effects due to the sqrt[s] energy dependence of the high p(T) slope and heavy quark energy loss is predicted to lead to surprising similarity of heavy quark suppression at RHIC and LHC. 相似文献
12.
The experimentally measurable effects related to extra dimensional gravity in a RS-type brane world are estimated. Two options of the RS framework (with small and large curvature) are considered. It is shown that physical signals of both can be detected by the joint experiment of the CMS and TOTEM Collaborations at the LHC. 相似文献
13.
We discuss the implementation of the “minimal” type III seesaw model, i.e. with one fermionic triplet, in FeynRules/MadGraph.
This is the first step in order to realize a real study of LHC data recorded in the LHC detectors. With this goal in mind,
we comment on the possibility of discovering this kind of new physics at the LHC running at 7 TeV with a luminosity of few
fb−1. 相似文献
14.
The photon-induced processes at the LHC provide clean experimentalconditions due to absence of the proton remnants, which might produce complementary and interesting results for tests of the standard model and for searching of new physics. In the context of the littlest Higgs model with T-parity, we consider the photon-induced production of the mirror quarks at the LHC. The cross sections for various production channels are calculated and asimply phenomenological analysis is performed by assuming leptonic decays. 相似文献
15.
Yongsheng Gao Liang Lu Xinlei Wang 《The European Physical Journal C - Particles and Fields》2006,45(3):659-667
The LHC experiments have great potential in discovering many possible new particles up to the TeV scale. The significance
calculation of an observation of a physics signal with known location and shape is no longer valid when either the location
or the shape of the signal is unknown. We find the current LHC significance calculation of new physics is over-estimated and
strongly depends on the specifics of the method and the situation it applies to. We describe general procedures for significance
calculation and comparing different search schemes. A new method uses maximum likelihood fits with floating parameters and
scans the parameter space for the best fit to the entire sample. We find that the new method is significantly more sensitive
than current method and is insensitive to the exact location of the new physics signal we search. 相似文献
16.
J Schukraft 《Pramana》2001,57(2-3):345-354
Ultrarelativisitc heavy ion physics is entering the new era of collider experiments with the start-up of RHIC at BNL and construction
for detectors at LHC well under way. At this cross-roads, the article will give a summary of the experimental program and
our current view of heavy ion physics at the LHC, concentrating in particular on physics topics that are different or unique
compared to current facilities. 相似文献
17.
R. Lafaye T. Plehn M. Rauch D. Zerwas 《The European Physical Journal C - Particles and Fields》2008,54(4):617-644
If new physics is found at the LHC (and the ILC) the reconstruction of the underlying theory should not be biased by assumptions
about high-scale models. For the mapping of many measurements onto high-dimensional parameter spaces we introduce SFitter
with its new weighted Markov chain technique. SFitter constructs an exclusive likelihood map, determines the best-fitting
parameter point and produces a ranked list of the most likely parameter points. Using the example of the TeV-scale supersymmetric
Lagrangian we show how a high-dimensional likelihood map will generally include degeneracies and strong correlations. SFitter
allows us to study such model-parameter spaces employing Bayesian as well as frequentist constructions. We illustrate in detail
how it should be possible to analyze high-dimensional new-physics parameter spaces like the TeV-scale MSSM at the LHC. A combination
of LHC and ILC measurements might well be able to completely cover highly complex TeV-scale parameter spaces. 相似文献
18.
A. G. Afonin V. I. Baranov V. T. Baranov G. I. Britvich A. P. Bugorskii M. K. Bulgakov A. A. Durum I. S. Lobanov A. N. Lun’kov A. V. Lutchev V. A. Maisheev Yu. E. Sandomirskii A. V. Skleznev Yu. A. Chesnokov P. N. Chirkov I. A. Yazynin A. A. Yanovich 《JETP Letters》2012,96(7):424-426
Bent crystals are used at large accelerators to deflect particle beams for extraction and collimation. Not only the deflection but also the focusing of beams by bent crystals can be required for recently formulated proposals for investigations at the Large Hadron Collider (LHC) with a fixed target. The experimental results on the focusing of a 50-GeV proton beam with a new crystal device, which can be used in a circulating beam of a large accelerator such as the LHC, have been reported. 相似文献
19.
A. Giovannini R. Ugoccioni 《The European Physical Journal C - Particles and Fields》2004,36(3):309-313
The study of possible new physics signals in global event properties in pp collisions in the TeV energy domain is extended from full phase-space to rapidity intervals experimentally accessible at LHC. The elbow structure in the total multiplicity distribution predicted in full phase-space is clearly present also in restricted rapidity intervals, leading to very strong charged particle correlations. It is also found that energy densities comparable to those reached in heavy ion collisions at RHIC could be attained in pp collisions at LHC.Received: 3 March 2004, Published online: 23 July 2004 相似文献
20.
Bodek A. Sarica U. Naples D. Ren L. 《The European Physical Journal C - Particles and Fields》2012,72(4):1-9
We present a set of recommendations for the presentation of LHC results on searches for new physics, which are aimed at providing a more efficient flow of scientific information between the experimental collaborations and the rest of the high energy physics community, and at facilitating the interpretation of the results in a wide class of models. Implementing these recommendations would aid the full exploitation of the physics potential of the LHC. 相似文献