J. Budagov

Proposal for chiral-boson search at LHC via their unique new signature

The resonance production of new chiral spin-1 bosons and their detection through the Drell-Yan process at the CERN LHC is considered. Quantitative evaluations of various differential cross sections of the chiral-boson production are made within the CalcHEP package. The new neutral chiral bosons can be observed as a Breit-Wigner resonance peak in the invariant-dilepton-mass distribution, as usual. However, unique new signatures of the chiral bosons exist. First, there is no Jacobian peak in the lepton transverse-momentum distribution. Second, the lepton angular distribution in the Collins—Soper frame for the high on-peak invariant masses of the lepton pairs has a peculiar “swallowtail” shape.

A laser sensor of a seismic slope of the Earth surface

A principally new method of the measurement of a seismic slope of the Earth surface is suggested. The method makes it possible to stabilize the position of the laser beam as a highly extended coordinate axis in the metrological support of the precision construction of large-scale physical installations. The method has been tested experimentally: for the first time, low-frequency periodic angular oscillations have been registered with an amplitude of 5 × 10−7 rad and the noise registration value of 2.5 × 10−8 rad. The measurements were taken at CERN, during the construction of the spectrometric complex ATLAS.

Laser beam fiducial line application for metrological purposes

The possibility for a collimated one-mode laser beam used as a fiducial line is considered. The technology for an “extended” laser beam formation and application for a much-extended fiducial line is proposed.

On resonance search in dilepton events at the LHC

The main distribution for a bump search is the dilepton-invariant-mass distribution with appropriate cut on an absolute value of pseudorapidity difference Δη ≡ |η1 − η2| between the two leptons. The back-ground from the Standard Model Drell-Yan process contributes mainly to the central pseudorapidity region Δη ≈ 0. By contrast, the excited bosons lead to a peak at Δη ≈ 1.76. We show that this property allows one to enhance the significance of their bump search by means of the new cut optimization. Nevertheless, in order to confirm an observation of the bump and reveal the resonance nature, other angular distributions should be used in addition.

The precision laser inclinometer long-term measurement in thermo-stabilized conditions (First Experimental Data)

The Precision Laser Inclinometer was tested at thermo-stabilized conditions and the ground angular stability of 1 μrad (observation during 24 h) and 7nrad (observation during 60 min) was measured.

The laser reference line method and its comparison to a total station in an ATLAS like configuration

A new type of measuring system, the Laser Reference Line, is proposed as a metrological tool and can be used within limited space to ensure a precise installation along an axis on the ATLAS interaction point. A simplified ATLAS like beam pipe mock-up is used for this test. The coordinates of the beam pipe are measured three times using the new method and a Total Station. The measurements agree within the measurement error of the Total Station, which indicates that the precision of the laser reference line is suitable for this specific task in the ATLAS experiment.

A unique signal of excited bosons in dijet data from pp collisions

With this note we would like to draw attention to a possible novel signal of new physics in dijet data at the hadron colliders. Usually it is accepted that almost all exotic models predict that these two jets populate the central (pseudo)rapidity region where y1,2 ≅ 0. Contrary, the excited bosons do not contribute into this region, but produce an excess of dijet events over the almost flat QCD background in χ = exp|y1−y2| away from this region. For the special choice of parameters this could lead to a dip in the centrality ratio distribution over the dijet invariant mass instead of a bump, expected for the most exotic models.

The calibration of the Precision Laser Inclinometer

The calibration methods of the two-coordinate Precision Laser Inclinometer are presented. For the inclinometer studied sample of the, the calibration coefficients 630 ± 70 and 531 ± 66 μrad/V have been determined by two independent methods.

The sensitivity limitation by the recording ADC to Laser Fiducial Line and Precision Laser Inclinometer

For metrology set-ups using a laser beam (The Laser Fiducial Line, the Precision Laser Inclinometer) the recording noise has been determined. This noise is limiting the measurement precision of the beam displacement Δx and consequently the precision Δψ of measurement of the beam inclination angle. For a 10 mm laser beam diameter the Δx = ±2.9 × 10–9 m has been obtained. For a one-mode laser beam with a primary diameter of 10 mm and with subsequent focusing a value of Δψ = ±1.7 × 10–11 rad has been found.

On the LHC observation of gluinos from the Egret-preferred region

AbstractProspects for observation of a SUSY-like signal from two gluinos