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41.
We discuss various reactions at futuree
+
e
– and colliders involving real (beamstrahlung or backscattered laser) or quasi-real (bremsstrahlung) photons in the initial state and hadrons in the final state. The production of two central jets with large transverse momentump
T
is described in some detail; we give distributions for the rapidity andp
T
of the jets as well as the di-jet invariant mass, and discuss the relative importance of various initial state configurations and the uncertainties that arise from the at present rather poor knowledge of the parton content of the photon. We also present results for mono-jet production where one jet goes down a beam pipe, for the production of charm, bottom and top quarks, and for single production ofW andZ bosons. Where appropriate, the two-photon processes are compared with annihilation reactions leading to similar final states. We also argue that the behaviour of the total inelastic cross section at high energies will probably have little impact on the severity of background problems caused by soft and semi-hard (minijet) two-photon reactions. We find very large differences in cross sections for all two-photon processes between existing desings for futuree
+
e
– colliders, due to the different beamstrahlung spectra; in particular, both designs with 1 and 1 events per bunch crossing exist. The number of hadronic two-photon events is expected to rise quickly with the beam energy. Hadronic backgrounds will be even worse if thee
+
e
– collider is converted into a collider. 相似文献
42.
R. M. Godbole A. Grau G. Pancheri Y. N. Srivastava 《The European Physical Journal C - Particles and Fields》2009,63(1):69-85
In this paper we apply to the photoproduction total cross section a model we have proposed for purely hadronic processes and
which is based on QCD mini-jets and soft gluon re-summation. We compare the predictions of our model with the HERA data as
well as with other models. For cosmic rays, our model predicts substantially higher cross sections at TeV energies than models
based on factorization, but lower than models based on mini-jets alone, without soft gluons. We discuss the origin of this
difference. 相似文献
43.
Anna Celaya Anant P. Godbole Mandy Rae Schleifer 《Methodology and Computing in Applied Probability》2006,8(3):357-371
The classical Erdős–Ko–Rado (EKR) Theorem states that if we choose a family of subsets, each of size k, from a fixed set of size
, then the largest possible pairwise intersecting family has size
. We consider the probability that a randomly selected family of size t=t
n
has the EKR property (pairwise nonempty intersection) as n and k=k
n
tend to infinity, the latter at a specific rate. As t gets large, the EKR property is less likely to occur, while as t gets smaller, the EKR property is satisfied with high probability. We derive the threshold value for t using Janson’s inequality. Using the Stein–Chen method we show that the distribution of X
0, defined as the number of disjoint pairs of subsets in our family, can be approximated by a Poisson distribution. We extend
our results to yield similar conclusions for X
i
, the number of pairs of subsets that overlap in exactly i elements. Finally, we show that the joint distribution (X
0, X
1, ..., X
b
) can be approximated by a multidimensional Poisson vector with independent components.
相似文献
44.
45.
Bhavana Gupta Lin Zhang Ambrose Ashwin Melvin Bertrand Goudeau Laurent Bouffier Alexander Kuhn 《Chemical science》2021,12(6):2071
Rational design and shaping of soft smart materials offer potential applications that cannot be addressed with rigid systems. In particular, electroresponsive elastic materials are well-suited for developing original active devices, such as pumps and actuators. However, applying the electric stimulus requires usually a physical connection between the active part and a power supply. Here we report about the design of an electromechanical system based on conducting polymers, enabling the actuation of a wireless microfluidic pump. Using the electric field-induced asymmetric polarization of miniaturized polypyrrole tubes, it is possible to trigger simultaneously site-specific chemical reactions, leading to shrinking and swelling in aqueous solution without any physical connection to a power source. The complementary electrochemical reactions occurring at the opposite extremities of the tube result in a differential change of its diameter. In turn, this electromechanical deformation allows inducing highly controlled fluid dynamics. The performance of such a remotely triggered electrochemically active soft pump can be fine-tuned by optimizing the wall thickness, length and inner diameter of the material. The efficient and fast actuation of the polymer pump opens up new opportunities for actuators in the field of fluidic or microfluidic devices, such as controlled drug release, artificial organs and bioinspired actuators.Tubular conducting polymer actuators are used for developing a wireless electropumping device. Bipolar electrochemistry, allowing symmetry breaking in terms of polarization and electrochemical reactions, is the key ingredient for efficient pumping. 相似文献
46.
Rohini M. Godbole Agnes Grau Rohit Hegde Giulia Pancheri Yogi Srivastava 《Pramana》2006,66(4):657-668
In this note, we summarize and compare various model predictions forpp total cross-section σ
tot
pp
, giving an estimate of the range of predictions for the total cross-section, σ
tot
pp
expected at the LHC. We concentrate on the results for σ
tot
pp
obtained in a particular QCD based model of the energy dependence of the total cross-section, including the effect of soft
gluon radiation. We obtain the range of predictions in this model by exploring the allowed range of model parameters. We further
give a handy parametrisation of these results which incidentally spans the range of various other available predictions at
the LHC as well 相似文献
47.
Synthesis and photoluminescence (PL) investigations of lithium metasilicate doped with Eu3+, Tb3+ and Ce3+ were carried out. PL spectra of Eu-doped sample showed peaks corresponding to the 5D0→7Fj (j=1, 2, 3 and 4) transitions under ultraviolet excitation. Strong red emission coming from the hypersensitive 5D0→7F2 transition of Eu3+ ion suggested the presence of the dopant ion in structurally disordered environment. Tb3+-doped silicate sample showed blue-green emission corresponding to the 5D4→7Fj (j=6, 5 and 4) transitions. Ce-doped sample under excitation from UV, showed a broad emission band in the region 350-370 nm with shoulders around 410 nm. The fluorescence lifetimes of Eu3+ and Tb3+ ions were found out to be 790 and 600 μs, respectively. For Ce3+, the lifetime was of the order of 45 ns. PL spectra of the europium- and terbium-doped samples were compared with commercial red (Y2O3:Eu3+) and green (LaPO4:Tb3+) phosphors, respectively. It was found that the emission from the doped silicate sample was 37% of the commercial phosphor in case of the Tb-doped sample and 8% of the commercial phosphor in case of the Eu-doped sample. 相似文献
48.
A. G. Page S. V. Godbole Sandhya Deshkar Y. Babu B. D. Joshi 《Fresenius' Journal of Analytical Chemistry》1977,287(4-5):304-309
Summary An emission spectrographic method has been developed for the estimation of 22 metallic impurities in plutonium dioxide using carrier-distillation technique Silver chloride at 5% concentration in a charge of 100 mg has been used as the carrier. Mixed oxide standards containing 10% PuO2 have been used for the analysis of matching composition of plutonium samples. Precision and accuracy determinations of the synthetic samples indicate 7–16% deviation for most of the elements. The work described includes analysis of reference samples and matrix effect studies. The method is suitable for the chemical quality control analysis of plutonium oxide to be used for Fast Breeder Test Reactor (FBTR) fuel.
Spektralanalytische Bestimmung von metallischen Verunreinigungen in PuO2
Zusammenfassung Mit dem Verfahren der Trägerdestillation können 22 Elemente in Plutoniumdioxid spektralanalytisch erfaßt werden. Als Träger dient 5% Silberchlorid in je 100 mg. Mischoxid-Standards mit 10% PuO2 wurden verwendet. Bei der Untersuchung von Genauigkeit und Reproduzierbarkeit synthetischer Proben wurden für die meisten Elemente Abweichungen von 7–16% festgestellt. Matrixeinflüsse wurden ebenfalls untersucht sowie Analysenergebnisse für bestimmte Bezugsstandards mitgeteilt. Das Verfahren eignet sich für die Qualitätskontrolle von PuO2-Brennstoffen für schnelle Brutreaktoren.相似文献
49.
A. Belyaev I. A. Christidi A. De Roeck R. M. Godbole B. Mellado A. Nyffeler C. Petridou D. P. Roy 《Pramana》2009,72(1):229-237
We report on a plan to establish a ‘Dictionary of LHC Signatures’, an initiative that started at the WHEPP-X workshop in Chennai,
January 2008. This study aims at the strategy of distinguishing 3 classes of dark matter motivated scenarios such as R-parity conserved supersymmetry, little Higgs models with T-parity conservation and universal extra dimensions with KK-parity for generic cases of their realization in a wide range
of the model space. Discriminating signatures are tabulated and will need a further detailed analysis.
相似文献
50.
We investigate the possibilities of studying new physics in various processes of t-quark production using kinematical distributions of the secondary lepton coming from decay of t quarks. We show that the angular distributions of the secondary lepton are insensitive to the anomalous tbW vertex and hence are pure probes of new physics in a generic process of t-quark production. The effects of t polarization on the distributions of the decay lepton are demonstrated for top-pair production process at a γγ-collider mediated by a heavy Higgs boson.
相似文献