Alexei Raspereza

We report on the design, construction and performance of a prototype for a high-granularity tile hadronic calorimeter for a future international linear collider detector. Scintillating tiles are read out via wavelength-shifting fibers that guide the scintillation light to a novel photodetector, the silicon photomultiplier. A prototype has been tested using a positron test beam at DESY. The results are compared with a reference prototype calorimeter equipped with multichannel vacuum photomultipliers. Detector calibration, noise, linearity and stability are discussed, and the energy response in a 1–6 GeV positron beam is compared with simulations. The present results demonstrate that the silicon photomultiplier is well-suited as photodetectors in calorimeters and thus has been selected for the construction of a 1m3 calorimeter prototype to operate in hadron beams.

<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> For the detection of secondary vertices of long lived particles containing bottom and charm quarks at the International Linear Collider (ILC), a DEPFET pixel detector is one of the technologically favored options. In a DEPFET sensor a MOSFET pixel detector is integrated on a sidewards depleted silicon bulk sensor, thus combining the advantages of a fully depleted silicon sensor with in-pixel amplification. DEPFET pixel matrices have been characterized in a high energy particle beam. Since the DEPFET is a very high precision device, given its large <formula formulatype="inline"><tex>${\rm S}/{\rm N}$</tex> </formula> (<formula formulatype="inline"><tex>$&gt; 100$</tex></formula>) and small pixel size (36<formula formulatype="inline"><tex>$\, \times 22 ~\mu {\rm m}^{2}$</tex></formula>), a DEPFET based pixel telescope consisting of 5 DEPFETs has been developed. The uncertainty on the predicted position for a device under test (DUT) positioned inside the telescope was found to be 1.4 <formula formulatype="inline"><tex>$\mu{\rm m}$</tex></formula> with the existing device, due to the limited performance of two of the five DEPFET planes. A DEPFET telescope built of 5 modules equivalent to the best plane presented here, would have a track extrapolation error as low as 0.65 <formula formulatype="inline"><tex>$\mu{\rm m}$</tex></formula> at the DUT plane. </para>

In a DEPleted Field Effect Transistor (DEPFET) sensor a MOSFET is integrated on a sidewards depleted p-on-n silicon detector, thereby combining the advantages of a fully depleted silicon sensor with in-pixel amplification. A 450 μm thick DEPFET was tested in a testbeam. The S/N was found to be larger than 110. The position resolution is better than 5 μm. At a seed cut of 7σ, the efficiency and purity are both close to 100%. In the readout chip a zero-suppression capability is implemented. The functionality was demonstrated using a radio-active source. The predicted impact parameter resolution of a 50 μm thick DEPFET vertex detector, is much better than required for the International Linear Collider (ILC).

A bstract A search for new top quark interactions is performed within the framework of an effective field theory using the associated production of either one or two top quarks with a Z boson in multilepton final states. The data sample corresponds to an integrated luminosity of 138 fb − 1 of proton-proton collisions at $$ \sqrt{s} $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msqrt> <mml:mi>s</mml:mi> </mml:msqrt> </mml:math> = 13 TeV collected by the CMS experiment at the LHC. Five dimension-six operators modifying the electroweak interactions of the top quark are considered. Novel machine-learning techniques are used to enhance the sensitivity to effects arising from these operators. Distributions used for the signal extraction are parameterized in terms of Wilson coefficients describing the interaction strengths of the operators. All five Wilson coefficients are simultaneously fit to data and 95% confidence level intervals are computed. All results are consistent with the SM expectations.

There are many possibilities for new physics beyond the Standard Model that feature non-standard Higgs sectors. These may introduce new sources of CP violation, and there may be mixing between multiple Higgs bosons or other new scalar bosons. Alternatively, the Higgs may be a composite state, or there may even be no Higgs at all. These non-standard Higgs scenarios have important implications for collider physics as well as for cosmology, and understanding their phenomenology is essential for a full comprehension of electroweak symmetry breaking. This report discusses the most relevant theories which go beyond the Standard Model and its minimal, CP-conserving supersymmetric extension: two-Higgs-doublet models and minimal supersymmetric models with CP violation, supersymmetric models with an extra singlet, models with extra gauge groups or Higgs triplets, Little Higgs models, models in extra dimensions, and models with technicolour or other new strong dynamics. For each of these scenarios, this report presents an introduction to the phenomenology, followed by contributions on more detailed theoretical aspects and studies of possible experimental signatures at the LHC and other colliders.

We report upon the performance of an analog hadron calorimeter prototype, where plastic scintillator tiles are read out with wavelength-shifting fibers coupled to avalanche photodiodes. This prototype configuration has been tested using a positron beam at DESY with energies between 1 and 6 GeV. We present different detector calibration methods, show measurements for noise, linearity, and energy resolution and discuss gain monitoring with an LED system. The results are in good agreement with our simulation studies and previous measurements using silicon photomultiplier readout.

This report reviews the properties of Higgs bosons in the Standard Model (SM) and its various extensions. We give an extensive overview about the potential of the ILC operated at centre-of-mass energies up to 1 TeV (including the gamma gamma option) for the determination of the Higgs boson properties. This comprises the measurement of the Higgs boson mass, its couplings to SM fermions and gauge bosons, and the determination of the spin and the CP quantum numbers of the Higgs. The extensions of the SM that are analyzed in more detail are heavy SM-like Higgs bosons, heavy Higgs bosons in the framework of Supersymmetry (SUSY) and further exotic scenarios. We review recent theoretical developments in the field of Higgs boson physics. The important question what the ILC can contribute to Higgs boson physics after the LHC, the LHC/ILC interplay and synergy is discussed. The impact of Higgs boson physics on cosmology in several SUSY frameworks is analyzed. The impact of the accelerator and dector performance on the precision of measurements are discussed in detail. We propose a strategy to optimize future analyses. Open questions arising for the various topics are listed, further topics of study and corresponding roadmaps are suggested.

Based on a novel shower reconstruction algorithm, the study of two particle separation with tile hadron calorimeter (HCAL) is performed. The separability of two close-by particles is found to be strongly dependent on transverse and longitudinal segmentation of tile HCAL.

This report reviews the properties of Higgs bosons in the Standard Model (SM) and its various extensions. We give an extensive overview of the potential of the ILC operated at center-ofmass energies up to 1 TeV (including the γγ collider option) for the determination of the Higgs boson properties. This includes the measurement of the Higgs boson mass, its couplings to SM fermions and gauge bosons, and the determination of the spin and the CP quantum numbers of the Higgs. We also discuss extensions of the SM, including heavy SM-like Higgs bosons, heavy Higgs bosons in the framework of Supersymmetry (SUSY) and more exotic scenarios. We review recent theoretical developments in the field of Higgs boson physics, and the impact of Higgs boson physics on cosmology in several SUSY frameworks is considered. The important questions as to what the ILC can contribute to Higgs boson physics after the LHC, the LHC/ILC interplay and synergy, are addressed. The impact of the accelerator and detector performance on the precision of measurements are discussed in detail and we propose a strategy to optimize future analyses. Open questions arising for the various topics are listed, and further topics of study and corresponding roadmaps are suggested.

A Particle Flow Algorithm (PFA) with the minimized dependence on the detector geometry is presented. Current PFA implementation includes procedures of the track reconstruction, calorimeter clustering, and individual particle reconstruction and is meant as a tool for the optimization of the International e+e- Linear Collider detector.

A theoretical investigation of alumina micron and submicron multichannel electron amplifiers was carried out. The theoretical study was based on multiplier performance Monte-Carlo simulation and general concepts of secondary electron emission theory. The simulation was performed for multipliers for which the length-to-diameter ratio was varied from 40 to 60 and the bias voltage from 600 to 1400 V. Calculations were made for the linear mode of multiplier operation under single electron stimulus. The simulation showed that alumina plates of the considered configurations are expected to possess a high gain (> 1000 at applied voltages exceeding 1.2 kV). The simulation also demonstrated that submicrochannel multipliers have faster response (< 30 ps), better temporal resolution (< 10 ps) and higher tolerance to strong axial (parallel with respect to channel axis) magnetic fields (up to ∼ 4 T) than microchannel plates with the same length-to-diameter ratios. Anodic alumina submicrochannel plates with channel diameter 0.07–0.4 μm, length-to-diameter ratio up to 300 and an effective open area up to ∼ 50% have been produced.

Based on a novel shower reconstruction algorithm, the study of two particle separation with tile hadron calorimeter (HCAL) is performed. The separability of two close-by particles is found to be strongly dependent on transverse and longitudinal segmentation of tile HCAL.

The potential of a linear e + e- collider operated at a centre-of-mass energy of 350 GeV is studied for the measurement of the Higgs boson mass. An integrated luminosity of 500 fb-1 is assumed. For Higgs boson masses of 120, 150 and 180 GeV the uncertainty on the Higgs boson mass measurement is estimated to be 40, 65 and 70 MeV, respectively. The effects of beam related systematics, namely a bias in the beam energy measurement, the beam energy spread and the luminosity spectrum due to beamstrahlung, on the precision of the Higgs boson mass measurement are investigated. In order to keep the systematic uncertainty on the Higgs boson mass well below the level of the statistical error, the beam energy measurement must be controlled with a relative precision better than 10-4.

The process ee-->ZH allows to measure the Higgs boson in the recoil mass spectrum against the Z boson without any assumptions on the Higgs boson decay. We performed a full simulation and reconstruction of ee-->ZH using the MOKKA and MARLIN packages describing the LDC detector. The Z is reconstructed from its decays into electrons and muons. The mass of the Higgs boson is set to 120 GeV. Assuming a centre-of-mass energy of 250 GeV and an integrated luminosity of 50/fb the Higgs boson mass and the Higgs-strahlung cross section can be measured with a precision of 120 MeV and 9%, respectively.

New precise data of the $\Lambda^0$ polarization are obtained in the EXCHARM experiment at the Serpukhov accelerator. The $\Lambda^0$ s have been produced in nC interactions in the neutron energy interval 40–70 GeV and detected in the kinematic range of $0.1\lesssim x_{\mathrm{F}} \lesssim 0.6$ and $0.2\le p_{\mathrm{t}} \le 1.2$ GeV/c. The obtained results are compared with other measurements in the pp and pA interactions.

The Standard Model (SM) [1] predicts one Higgs boson as a remnant from the spontaneoussymmetry breakingmechanism [2]. This mechanism allows fermions and the W and Z bosonsto acquire their masses by interaction with the Higgs field. To discover the Higgs boson,therefore, is of crucial interest to complete the SM. Electroweak precision measurementssuggest the mass of the Higgs boson to be of the order O(100GeV). Direct searches atLEP have set a lower mass limit of 114 GeV. A Higgs boson with a mass above 114 GeVwill be accessible in the experiments at the Large Hadron Collider (LHC). However, to besure about the nature of the particle found, it is necessary to measure its properties such asmass, width, charge, spin, parity, couplings to other particles, and self-couplings to test theinternal consistency of the SM, or to find hints for new physics.For the determination of at least some of these quantities, LHC will not be sufficient.At the future International Linear Collider (ILC), we will have the chance to investigatethe properties of new particles with high precision in all details. This e

A Particle Flow Algorithm (PFA) with the minimized dependence on the detector geometry is presented. Current PFA implementation includes procedures of the track reconstruction, calorimeter clustering, and individual particle reconstruction and is meant as a tool for the optimization of the International e+e- Linear Collider detector.

The effect of beam related systematics, namely uncertainty in the beam energy and differential luminosity spectrum measurements and beam energy spread on the precision of the Higgs boson mass measurement at a future linear e+e- collider is investigated.

The International Linear Collider (ILC) will have an extremely rich physics program and it will be an ideal experimental tool to explore the structure of the Electroweak Symmetry Breaking.If the Higgs mechanism is realised in Nature, the ILC will allow for a precise determination of the Higgs boson profile.Furthermore, alternative models of Electroweak Symmetry Breaking and theories beyond the Standard Model will be probed.In this paper the features of the machine are outlined, the detector performance goals are discussed and the physics potential of the linear collider is reviewed.

The process ee--&gt;ZH allows to measure the Higgs boson in the recoil mass spectrum against the Z boson without any assumptions on the Higgs boson decay. We performed a full simulation and reconstruction of ee--&gt;ZH using the MOKKA and MARLIN packages describing the LDC detector. The Z is reconstructed from its decays into electrons and muons. The mass of the Higgs boson is set to 120 GeV. Assuming a centre-of-mass energy of 250 GeV and an integrated luminosity of 50/fb the Higgs boson mass and the Higgs-strahlung cross section can be measured with a precision of 120 MeV and 9%, respectively.

We study the potential of the TESLA linear collider operated at a center-of-mass energy of 500 to 1000 GeV for the measurement of the neutral Higgs boson properties within the framework of the MSSM. The process of associated Higgs boson production with subsequent decays of Higgs bosons into b-quark and tau-lepton pairs is considered. An integrated luminosity of 500 fb^{-1} is assumed at each energy. The Higgs boson masses and production cross sections are measured by reconstructing the bbbb and bbττfinal states. The precision of these measurements is evaluated in dependence of the Higgs boson masses. Under the assumed experimental conditions a statistical accuracy ranging from 0.1 to 1.0 GeV is achievable on the Higgs boson mass. The topological cross section σ(e+e- -&gt; HA -&gt; bbbb) can be determined with the relative precision of 1.5 - 6.6 % and cross sections σ(e+e- -&gt; HA -&gt; bb ττ) and σ(e+e- -&gt; HA -&gt; ττbb) with precision of 4 - 30 %. Constraints on the Higgs boson widths can be set exploiting bbττchannel. The 5σdiscovery limit corresponds to the Higgs mass of around 385 GeV for the degenerate Higgs boson masses in the HA -&gt; bbbb channel at \sqrts = 800 GeV with integrated luminosity of 500 fb^{-1}. The potential of the Higgs mass determination for the benchmark point SPS 1a for the process e+e- -&gt; HA -&gt; bbbb at \sqrt{s} = 1 TeV and luminosity 1000 fb^{-1} is investigated.

This report reviews the properties of Higgs bosons in the Standard Model (SM) and its various extensions. We give an extensive overview of the potential of the ILC operated at center-of-mass energies up to 1 TeV (including the γγ collider option) for the determination of the Higgs boson properties. This includes the measurement of the Higgs boson mass, its couplings to SM fermions and gauge bosons, and the determination of the spin and the CP quantum numbers of the Higgs. We also discuss extensions of the SM, including heavy SM-like Higgs bosons, heavy Higgs bosons in the framework of Supersymmetry (SUSY) and more exotic scenarios. We review recent theoretical developments in the field of Higgs boson physics, and the impact of Higgs boson physics on cosmology in several SUSY frameworks is considered. The important questions as to what the ILC can contribute to Higgs boson physics after the LHC, the LHC/ILC interplay and synergy, are addressed. The impact of the accelerator and detector performance on the precision of measurements are discussed in detail and we propose a strategy to optimize future analyses. Open questions arising for the various topics are listed, and further topics of study and corresponding roadmaps are suggested.

This paper shortly reports on the results of Higgs boson searches performed at LEP and Tevatron. No signal is found and limits on the mass and couplings of the Higgs boson are derived. Interpreting the data in the framework of the Standard Model, the 95% C.L. lower limit of 114.4 GeV on the Higgs boson mass is obtained.

This paper shortly reports on the results of Higgs boson searches performed at LEP and Tevatron. No signal is found and limits on the mass and couplings of the Higgs boson are derived. Interpreting the data in the framework of the Standard Model, the 95% C.L. lower limit of 114.4 GeV on the Higgs boson mass is obtained.

This paper shortly reports on the results of Higgs boson searches performed at LEP and Tevatron. No signal is found and limits on the mass and couplings of the Higgs boson are derived. Interpreting the data in the framework of the Standard Model, the 95% C.L. lower limit of 114.4 GeV on the Higgs boson mass is obtained.

This paper shortly reports on the results of Higgs boson searches performed at LEP and Tevatron. No signal is found and limits on the mass and couplings of the Higgs boson are derived. Interpreting the data in the framework of the Standard Model, the 95% C.L. lower limit of 114.4 GeV on the Higgs boson mass is obtained.