A new electrophysical method is proposed for liquid products rapid diagnosis of quality and identification. The method is widely prospective for practical application.
Internal jet structure in dijet production in deep-inelastic scattering is measured with the H1 detector at HERA. Jets with transverse energies
E
T,Breit
> 5 GeV are selected in the Breit frame ...employing
k
⊥ and cone jet algorithms. In the kinematic region of ssquared momentum transfers 10 <
Q
2 ⪅
s 120 GeV
2 and Bjorken−
x values 2 < 10
−4 ⪅
x
Bj ⪅ 8 × 10
−3, jet shapes and subjet multiplicities are measured as a function of a resolution parameter. Distributions of both observables are corrected for detector effects and presented as functions of the transverse jet energy and jet pseudo-rapidity. Dependences of the jet shape and the average number of subjets on the transverse energy and the pseudo-rapidity of the jet are observed. With increasing transverse jet energies and decreasing pseudo-rapidities, i.e. towards the photon hemisphere, the jets are more collimated. QCD models give a fair description of the data.
The reaction
e
+
p→
e
+
X is studied with the H1 detector at
Hera. The data cover momentum transfers
Q
2 between
200
GeV
2
and
30
000
GeV
2
and correspond to an integrated luminosity of
35.6
pb
−1
. ...The differential cross section d
σ/d
Q
2 is compared to the Standard Model expectation for neutral current scattering and analysed to search for
(
e
̄
e)(
q
̄
q)
contact interactions. No evidence for new phenomena is observed. The results are used to set limits on scales within models of electron–quark compositeness, quark form factors and the exchange of virtual heavy leptoquarks. A search for gravitational effects mediated through the exchange of virtual gravitons which propagate into large extra dimensions is presented.
A search for scalar and vector leptoquarks coupling to first generation fermions is performed in the H1 experiment at the ep collider HERA. The analysis uses e−p data collected in 1998 and 1999 at a ...centre-of-mass energy of 320 GeV, corresponding to an integrated luminosity of ∼15 pb−1. No evidence for the direct production of such particles is found in a data sample with a large transverse momentum final state electron or with large missing transverse momentum, and constraints on leptoquark models are established. For a Yukawa coupling of electromagnetic strength leptoquarks are excluded for masses up to ∼290 GeV. This analysis complements the leptoquark searches performed previously using data collected whilst HERA was operating with positrons instead of electrons.
Di-jet event rates have been measured for deep-inelastic scattering in the kinematic domain \(5 \lesssim Q^2 \lesssim 100\) GeV\(^2\) and \(10^{-4} \lesssim x_{Bj} \lesssim 10^{-2}\), and for jet ...transverse momenta squared \(p_t^{*2}\gtrsim Q^2\). The analysis is based on data collected with the H1 detector at HERA in 1994 corresponding to an integrated luminosity of about 2 pb\(^{-1}\). Jets are defined using a cone algorithm in the photon-proton centre of mass system requiring jet transverse momenta of at least 5 GeV. The di-jet event rates are shown as a function of \(Q^2\) and \(x_{Bj}\). Leading order models of point-like interacting photons fail to describe the data. Models which add resolved interacting photons or which implement the colour dipole model give a good description of the di-jet event rate. This is also the case for next-to-leading order calculations including contributions from direct and resolved photons.
Transverse momentum spectra of charged particles produced in deep inelastic scattering are measured as a function of the kinematic variables
x
and Q
2
using the H1 detector at the
epcollider HERA. ...The data are compared to different parton emission models, either with or without ordering of the emissions in transverse momentum. The data provide evidence for a relatively large amount of parton radiation between the current and the remnant systems.
Inclusive D*± production is measured in deep-inelastic ep scattering at HERA with the H1 detector. In addition, the production of dijets in events with a D*± meson is investigated. The analysis ...covers values of photon virtuality 2 ≤ Q2 ≤ 100 GeV2 and of inelasticity 0.05 ≤ y ≤ 0.7. Differential cross sections are measured as a function of Q2 and x and of various D*± meson and jet observables. Within the experimental and theoretical uncertainties all measured cross sections are found to be adequately described by next-to-leading order (NLO) QCD calculations, based on the photon-gluon fusion process and DGLAP evolution, without the need for an additional resolved component of the photon beyond what is included at NLO. A reasonable description of the data is also achieved by a prediction based on the CCFM evolution of partons involving the kT-unintegrated gluon distribution of the proton.
The mutations in mitochondrial DNA (mtDNA) arise at a higher frequency than in nuclear DNA, and their appearance in peripheral blood can be considered as a sensitive marker to estimate the level of ...genotoxic load. For revealing the presence of mutations in mtDNA of peripheral blood, we used the method of temporal temperature gradient gel electrophoresis (TTGE). The samples of whole blood DNA from four donor groups were used. Group I contained 10 young (23-26 years) donors and Group II 12 elderly (65-74 years) donors. Group III was formed from patients with breast cancer (12 women) past sessions of radio-chemotherapies (RCHT). Group IV was made of professionals of a nucleus plant occupationally exposed to chronic gamma-irradiation. PCR was carried out on four coding sequences and on one hypervariable sequence of the D-loop (DloopI) of mtDNA. PCR products were tested with TTGE. Most mutations were revealed in the DloopI. Heteroplasmy in the region of DloopI was registered in the blood of each donor of Group III 7 days after the RCHT session. Also, mutations in mtDNA Dloop1 were found in 6 of 13 individuals of Group IV. The blood of this donor group was taken 16 to 28 years after prolonged irradiations in a dose range of 250-350 cGy. In the elderly donor group, the same results were observed in 3 of 12 individuals. The results show that the method of TTGE can be used in mass analyses to assess the effects of radiation and other genotoxic agents in man by detection of unknown mutations in peripheral blood mtDNA.
Diffractive dijet production at HERA Adloff, C.; Anderson, M.; Andrieu, B. ...
The European physical journal. C, Particles and fields,
1/1999, Letnik:
6, Številka:
3
Journal Article
Recenzirano
Odprti dostop
Interactions of the type ep → eXY are studied, where the component X of the hadronic final state contains two jets and is well separated in rapidity from a leading baryonic system Y. Analyses are ...performed of both resolved and direct photoproduction and of deep-inelastic scattering with photon virtualities in the range 7.5 < Q2 < 80 GeV2. Cross sections are presented where Y has mass MY < 1.6 GeV, the squared four-momentum transferred at the proton vertex satisfies |t| < 1 GeV2 and the two jets each have transverse momentum pTjet > 5 GeV relative to the photon direction in the rest frame of X. Models based on a factorisable diffractive exchange with a gluon dominated structure, evolved to a scale set by the transverse momentum of the outgoing partons from the hard interaction, give good descriptions of the data. Exclusive production, as calculated in perturbative QCD using the squared proton gluon density, represents at most a small fraction of the measured cross section. The compatibility of the data with a breaking of diffractive factorisation due to spectator interactions in resolved photoproduction is investigated.
Inclusive D* production is measured in deep-inelastic ep scattering at HERA with the H1 detector. In addition, the production of dijets in events with a D* meson is investigated. The analysis covers ...values of photon virtuality 2< Q^2 <=100 GeV^2 and of inelasticity 0.05<= y <= 0.7. Differential cross sections are measured as a function of Q^2 and x and of various D* meson and jet observables. Within the experimental and theoretical uncertainties all measured cross sections are found to be adequately described by next-to-leading order (NLO) QCD calculations, based on the photon-gluon fusion process and DGLAP evolution, without the need for an additional resolved component of the photon beyond what is included at NLO. A reasonable description of the data is also achieved by a prediction based on the CCFM evolution of partons involving the k_T-unintegrated gluon distribution of the proton.
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