2,805 research outputs found
Soft Gluon Resummation Effects in Single Graviton Production at the CERN Large Hadron Collider in the Randall-Sundrum Model
We study QCD effects in single graviton production at the CERN Large Hadron
Collider (LHC) in the Randall-Sundrum (RS) Model. We present in detail the
complete next-to-leading order (NLO) QCD corrections to the inclusive total
cross sections. The NLO QCD corrections enhance significantly the total cross
sections and decrease efficiently the dependence of the total cross sections on
the factorization and renormalization scales. We also examine the uncertainty
of the total cross sections due to the parton distribution function (PDF)
uncertainties. For the differential cross sections on the transverse momentum
() of the graviton, within the CSS resummation formalism, we resum the
logarithmically-enhanced terms at small to all orders up to NLO
logatithmic accuracy. Combined with the fixed order calculations, we give
consistent predictions for both small and large .Comment: 26 pages, 13 figures; minor changes and misprints corrected; version
to appear in PR
Soft Gluon Resummation Effects in Single Slepton Production at Hadron Colliders
We investigate QCD effects in the production of a single slepton at hadron
colliders in the Minimal Supersymmetric Standard Model without R-parity. We
calculate the total cross sections and the transverse momentum distributions at
next-to-leading order in QCD. The NLO corrections enhance the total cross
sections and decrease the dependence of the total cross sections on the
factorization and renormalization scales. For the differential cross sections,
we resum all order soft gluon effects to give reliable predictions for the
transverse momentum distributions. We also compare two approaches to the
non-perturbative parametrization and found that the results are slightly
different at the Tevatron and are in good agreement at the LHC. Our results can
be useful to the simulation of the events and to the future collider
experiments.Comment: 26 pages, 12 figures, RevTeX4; Minor changes; Version to appear in
PR
Charged Higgs Production at Linear Colliders in Large Extra Dimensions
In the Two-Higgs-Doublet Model(2HDM) with large extra dimensions(LED), we
study the contributions of virtual Kaluza-Klein(KK) gravitons to 2HDM charged
Higgs production, especially in the two important production processes
and , at future linear colliders
(LC). We find that KK graviton effects can significantly modify these total
cross sections and also their differential cross sections compared to their
respective 2HDM values and, therefore, can be used to probe the effective scale
up to several TeV. For example, at TeV, the cross
sections for and in the 2HDM are
7.4fb for GeV and 0.003fb for TeV and
, while in LED they are 12.1fb and 0.01fb, respectively, for
Tev.Comment: 18 pages, 11 figures; a version to appear in PR
Functional renormalization group and variational Monte Carlo studies of the electronic instabilities in graphene near 1/4 doping
We study the electronic instabilities of near 1/4 electron doped graphene
using the functional renormalization group (FRG) and variational Monte-Carlo
method. A modified FRG implementation is utilized to improve the treatment of
the von Hove singularity. At 1/4 doping the system is a chiral spin density
wave state exhibiting the anomalous quantized Hall effect, or equivalently a
Chern insulator. When the doping deviates from 1/4, the
Cooper pairing becomes the leading instability. Our results suggest near 1/4
electron or hole doped graphene is a fertile playground for the search of Chern
insulators and superconductors.Comment: 7 pages, 8 figures, with technical details, published versio
Dynamic estimating the karst tunnel water inrush based on monitoring data during excavation
The tunnel water gushing has long been a difficult hydrogeological problem, especially in karst areas. It affects the entire process of tunnel construction, operation and maintenance. In view of the complex disaster-causing mechanism and difficult quantitative predictions of water inrush, several theoretical methods are adopted to realize dynamic assessment of water inrush in the progressive process of tunnel construction. According to a survey conducted in the Zoumaling tunnel near Chongqing, China, 62% of its total length, e.g., 1525 m is associated with karst(including a fault fracture zone). On the basis of collecting real-time monitoring data about water inrush in the excavated section of the Zoumaling tunnel, a fuzzy data analysis method has been used to analyze the content of seven common ions in the inflow water, which makes it possible to classify the groundwater types and to establish the hydrogeological model of the tunnel site. In order to forecast the possibility and quantity of water inrush, it is essential to accurately model the groundwater system spatially. The preliminary forecasting result about untapped section reveals a small possibility of a sudden water inflow disaster and 35,000 m3/d water inflow, which is close to the ultimately measured quantity of water. This study provides a theoretical reference for the prediction of water inrush during tunnel construction, and the main characteristic of this study is reflected in the real-time prediction of tunnel water inrush according to actual tunnel inflow of excavated sections. This approach can be applied in similar situations for the prediction of tunnel water inrush in other karst regions.Key words: karst region, tunnel water inrush; dynamic estimate; fuzzy cluster analysis.Pričakovana dinamika vdora vode v predore na podlagi meritev med njihovo gradnjoPojav vdiranja vode v predore je že dolgo časa poznana težava, še posebej na kraških območjih. Pojavlja se med celotno gradnjo predorov, njihovo uporabo in vzdrževanjem. Za proučevanje potencialnega pojava nesreč in težavnega napovedovanja količine vdora vode je bilo preizkušenih več različnih teoretičnih metod. Te omogočajo oceno dinamike vdora vode med celotnim procesom gradnje predorov. Pri predoru Zoumaling v bližini mesta Chongqing (Kitajska) približno 62 % dolžine predora (1525 m) poteka na območju krasa in čez prelomna območja. Na podlagi v realnem času zbranih podatkov o vdorih vode v izkopanih odsekih predora Zoumaling se je naredila analiza mehkih množic. Ta je bila uporabljena za analizo sedmih v vodi najbolj značilnih ionov in je omogočila razvrstitev podzemne vode v različne skupine, s tem pa izdelavo hidrogeološkega modela neposredne okolice predora. Za analizo verjetnosti vdora vode in njene možne količine je izdelava natančnega modela vodonosnika zelo pomembna. Prvi rezultati, ki se nanašajo na en še nedokončan odsek, kažejo na majhno možnost nenadnega vdora vode. Največja možna dnevna količina vdora je ocenjena na 35.000 m3, kar je blizu najvišje izmerjene dnevne količine dotoka. Pričujoča raziskava vzpostavlja teoretično podlago za napoved vdora vode v času gradnje predora, glavna posebnost pa je napoved vdora v realnem času na podlagi izmerjenega dotoka v že izkopanih odsekih predora. Predstavljen postopek in napovedi, ki jih omogoča, se lahko uporabijo v podobnih primerih tudi na drugih kraških območjih.Ključne besede: kraško območje, vdor vode v predore, pričakovana dinamika, analiza mehkih množic.
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