3,319 research outputs found
Next-to-leading order QCD corrections to a heavy resonance production and decay into top quark pair at the LHC
We present a complete next-to-leading order (NLO) QCD calculation to a heavy
resonance production and decay into a top quark pair at the LHC, where the
resonance could be either a Randall-Sundrum (RS) Kaluza-Klein (KK) graviton
or an extra gauge boson . The complete NLO QCD corrections can enhance the
total cross sections by about and for the and
the , respectively, depending on the resonance mass. We also explore in
detail the NLO corrections to the polar angle distributions of the top quark,
and our results show that the shapes of the NLO distributions can be different
from the leading order (LO) ones for the KK graviton. Moreover, we study the
NLO corrections to the spin correlations of the top quark pair production via
the above process, and find that the corrections are small.Comment: Published version in PR
Precise QCD predictions on top quark pair production mediated by massive color octet vector boson at hadron colliders
We present a theoretical framework for systematically calculating
next-to-leading order (NLO) QCD effects to various experimental observables in
models with massive COVB in a model independent way at hadron colliders.
Specifically, we show the numerical results for the NLO QCD corrections to
total cross sections, invariant mass distribution and AFB of top quark pairs
production mediated by a massive COVB in both the fixed scale (top quark mass)
scheme and the dynamical scale (top pair invariant mass) scheme. Our results
show that the NLO QCD calculations in the dynamical scale scheme is more
reasonable than the fixed scheme and the naive estimate of the NLO effects by
simple rescaling of the LO results with the SM NLO K-factor is not appropriate.Comment: 6 pages, 5 figures, 2 tables; version published in EPJ
One-loop Helicity Amplitudes for Top Quark Pair Production in Randall-Sundrum Model
In this paper, we show how to calculate analytically the one-loop helicity
amplitudes for the process induced by KK gluon,
using the spinor-helicity formalism. A minimal set of Feynman rules which are
uniquely fixed by gauge invariance and the color representation of the KK gluon
are derived and used in the calculation. Our results can be applied to a
variety of models containing a massive color octet vector boson.Comment: 37 pages, 10 figures, journal versio
QCD Effects in High Energy Processes
In this talk, some important QCD effects in Higgs physics, supersymmetry and
top physics, as well as the factorization and resummation techniques in QCD are
reviewed.Comment: LaTeX, 13 pages, uses ws-ijmpa.cls. Based on an invited talk at the
International Conference on QCD and Hadronic Physics, Beijing, China, June
16--20, 2005. Minor change
Next-to-leading order QCD corrections to the top quark decay via the Flavor-Changing Neutral-Current operators with mixing effects
In this paper detailed calculations of the complete
corrections to top quark decay widths are presented
(). Besides describing in detail the calculations in our previous
paper (arXiv:0810.3889), we also include the mixing effects of the
Flavor-Changing Neutral-Current (FCNC) operators for and , which were not considered in our previous paper. The results for are the same as in our previous paper. But the mixing effects can either
be large or small, and increase or decrease the branching ratios for and , depending on the values of the anomalous couplings
(,
and ).Comment: 21 pages, 12 figure
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Resource allocation for cache-enabled cloud-based small cell networks
To address the serious challenge of satisfying explosively increasing multimedia content requests from a massive number of users in mobile networks, deploying content caching in base stations to offload network traffic while satisfying content requests locally has been regarded as an effective approach to enhance the network performance. Moreover, content delivery via wireless transmissions in a cache-enabled mobile network needs to be optimized taking the proactive caching policy into consideration. Accordingly, in this paper, we investigate and propose an efficient resource allocation framework for cache-enabled cloud-based small cell networks (C-SCNs) to achieve the benefits of content caching by considering two phases, i.e., content placement and content delivery. In particular, for the content placement phase, we propose a low-complexity distributed popularity-based framework for allocating cache sizes of SBSs to popular contents, in order to offload network traffic and satisfy content requests locally. For the content delivery phase, we propose a low-complexity joint user association and subcarrier-power allocation scheme for min-rate guaranteed content delivery over orthogonal frequency division multiple access (OFDMA) based downlink transmissions. Trace-based simulations and numerical results demonstrate the effectiveness of the proposed schemes in the cache-enabled C-SCNs
Comparison of the Efficacy of MOE and PMO Modifications of Systemic Antisense Oligonucleotides in a Severe SMA Mouse Model
Spinal muscular atrophy (SMA) is a motor neuron disease. Nusinersen, a splice-switching antisense oligonucleotide (ASO), was the first approved drug to treat SMA. Based on prior preclinical studies, both 2'-O-methoxyethyl (MOE) with a phosphorothioate backbone and morpholino with a phosphorodiamidate backbone-with the same or extended target sequence as nusinersen-displayed efficient rescue of SMA mouse models. Here, we compared the therapeutic efficacy of these two modification chemistries in rescue of a severe mouse model using ASO10-29-a 2-nt longer version of nusinersen-via subcutaneous injection. Although both chemistries efficiently corrected SMN2 splicing in various tissues, restored motor function and improved the integrity of neuromuscular junctions, MOE-modified ASO10-29 (MOE10-29) was more efficacious than morpholino-modified ASO10-29 (PMO10-29) at the same molar dose, as seen by longer survival, greater body-weight gain and better preservation of motor neurons. Time-course analysis revealed that MOE10-29 had more persistent effects than PMO10-29. On the other hand, PMO10-29 appears to more readily cross an immature blood-brain barrier following systemic administration, showing more robust initial effects on SMN2 exon 7 inclusion, but less persistence in the central nervous system. We conclude that both modifications can be effective as splice-switching ASOs in the context of SMA and potentially other diseases, and discuss the advantages and disadvantages of each
Experimental realization of large-alphabet quantum key distribution protocol using orbital angular momentum entanglement
We experimentally demonstrate a quantum key distribution (QKD) protocol using
photon pairs entangled in orbit angular momentum (OAM). In our protocol, Alice
and Bob modulate their OAM states on each entangled pair with spatial light
modulators (SLMs), respectively. Alice uses a fixed phase hologram in her SLM,
while Bob designs different suitable phase holograms and uses them to
represent his -based information in his SLM. With coincidences, Alice can
fully retrieve the key stream sent by Bob without information reconciliation or
privacy amplification. We report the experiment results with N=3 and the sector
states with OAM eigenmodes l=1 and l=-1. Our experiment shows that the
coincidence rates are in relatively distinct value regions for the three
different key elements. Alice could recover fully Bob's keys by the protocol.
Finally, we discuss the security of the protocol both form the light way and
against the general attacks
Characterisation of volatile components of red and sparkling wines from a new wine grape cultivar 'Meili' (Vitis vinifera L.)
'Meili' (Vitis vinifera L.) is a new wine grape cultivar from China. Volatile profiles of red and sparkling wines made from 'Meili' grapes were analysed using stir bar sorptive extraction-gas chromatography-mass spectrometry in this study. Fiftyfive volatile compounds were quantified in both wines, and quantitative differences for most of the volatile compounds between 'Meili' wines were observed. 'Meili' sparkling wine had a greater content of esters, fatty acids and shikimic acid derivatives than 'Meili' red wine, although 'Meili' red wine had higher concentrations of alcohols, terpenoids and C13-norisoprenoids. On the basis of odour activity values, ethyl acetate, ethyl butanoate, ethyl hexanoate, ethyl octanoate, isoamyl acetate, ethyl 2-methylpropanoate, ethyl 3-methylbutanoate, octanoic acid, isoamyl alcohol, 2-phenyl ethanol, linalool, β-damascenone and β-ionone were considered as important aroma compounds in 'Meili' wines. For these compounds, 'Meili' sparkling wine had higher content of ethyl acetate, ethyl butanoate, ethyl hexanoate, ethyl octanoate and isoamyl acetate than 'Meili' red wine, while 'Meili' red wine had higher levels of isoamyl alcohol, 2-phenylethanol, linalool, β-damascenone and β-ionone. The concentration differences of aroma compounds due to the differential vinification procedures suggested the differences in sensory characteristics of the two types of wines. In particular, 'Meili' red wine had more rose aroma than 'Meili' sparkling wine.
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