E. Pérez

Theoretical and phenomenological implications of R-parity violation in supersymmetric theories are discussed in the context of particle physics and cosmology. Fundamental aspects include the relation with continuous and discrete symmetries and the various allowed patterns of R-parity breaking. Recent developments on the generation of neutrino masses and mixings within different scenarios of R-parity violation are discussed. The possible contribution of R-parity-violating Yukawa couplings in processes involving virtual supersymmetric particles and the resulting constraints are reviewed. Finally, direct production of supersymmetric particles and their decays in the presence of R-parity-violating couplings is discussed together with a survey of existing constraints from collider experiments.

HERAFitter is an open-source package that provides a framework for the determination of the parton distribution functions (PDFs) of the proton and for many different kinds of analyses in Quantum Chromodynamics (QCD). It encodes results from a wide range of experimental measurements in lepton–proton deep inelastic scattering and proton–proton (proton–antiproton) collisions at hadron colliders. These are complemented with a variety of theoretical options for calculating PDF-dependent cross section predictions corresponding to the measurements. The framework covers a large number of the existing methods and schemes used for PDF determination. The data and theoretical predictions are brought together through numerous methodological options for carrying out PDF fits and plotting tools to help to visualise the results. While primarily based on the approach of collinear factorisation, HERAFitter also provides facilities for fits of dipole models and transverse-momentum dependent PDFs. The package can be used to study the impact of new precise measurements from hadron colliders. This paper describes the general structure of HERAFitter and its wide choice of options.

Increasing luminosity at the Fermilab Tevatron collider has led the D0 collaboration to make improvements to its detector beyond those already in place for Run IIa, which began in March 2001. One of the cornerstones of this Run IIb upgrade is a completely redesigned level-1 calorimeter trigger system. The new system employs novel architecture and algorithms to retain high efficiency for interesting events while substantially increasing rejection of background. We describe the design and implementation of the new level-1 calorimeter trigger hardware and discuss its performance during Run IIb data taking. In addition to strengthening the physics capabilities of D0, this trigger system will provide valuable insight into the operation of analogous devices to be used at LHC experiments.

Abstract A precision measurement of jet cross sections in neutral current deep-inelastic scattering for photon virtualities $$5.5&lt;Q^2 &lt;80\,\mathrm {GeV}^2 $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mn>5.5</mml:mn><mml:mo>&lt;</mml:mo><mml:msup><mml:mi>Q</mml:mi><mml:mn>2</mml:mn></mml:msup><mml:mo>&lt;</mml:mo><mml:mn>80</mml:mn><mml:mspace /><mml:msup><mml:mrow><mml:mi>GeV</mml:mi></mml:mrow><mml:mn>2</mml:mn></mml:msup></mml:mrow></mml:math> and inelasticities $$0.2&lt;y&lt;0.6$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mn>0.2</mml:mn><mml:mo>&lt;</mml:mo><mml:mi>y</mml:mi><mml:mo>&lt;</mml:mo><mml:mn>0.6</mml:mn></mml:mrow></mml:math> is presented, using data taken with the H1 detector at HERA, corresponding to an integrated luminosity of $$290\,\mathrm {pb}^{-1}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mn>290</mml:mn><mml:mspace /><mml:msup><mml:mrow><mml:mi>pb</mml:mi></mml:mrow><mml:mrow><mml:mo>-</mml:mo><mml:mn>1</mml:mn></mml:mrow></mml:msup></mml:mrow></mml:math> . Double-differential inclusive jet, dijet and trijet cross sections are measured simultaneously and are presented as a function of jet transverse momentum observables and as a function of $$Q^2$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msup><mml:mi>Q</mml:mi><mml:mn>2</mml:mn></mml:msup></mml:math> . Jet cross sections normalised to the inclusive neutral current DIS cross section in the respective $$Q^2$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msup><mml:mi>Q</mml:mi><mml:mn>2</mml:mn></mml:msup></mml:math> -interval are also determined. Previous results of inclusive jet cross sections in the range $$150&lt;Q^2 &lt;15{,}000\,\mathrm {GeV}^2 $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mn>150</mml:mn><mml:mo>&lt;</mml:mo><mml:msup><mml:mi>Q</mml:mi><mml:mn>2</mml:mn></mml:msup><mml:mo>&lt;</mml:mo><mml:mn>15</mml:mn><mml:mo>,</mml:mo><mml:mn>000</mml:mn><mml:mspace /><mml:msup><mml:mrow><mml:mi>GeV</mml:mi></mml:mrow><mml:mn>2</mml:mn></mml:msup></mml:mrow></mml:math> are extended to low transverse jet momenta $$5&lt;P_\mathrm{T}^\mathrm{jet} &lt;7\,\mathrm {GeV} $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mn>5</mml:mn><mml:mo>&lt;</mml:mo><mml:msubsup><mml:mi>P</mml:mi><mml:mrow><mml:mi>T</mml:mi></mml:mrow><mml:mi>jet</mml:mi></mml:msubsup><mml:mo>&lt;</mml:mo><mml:mn>7</mml:mn><mml:mspace /><mml:mi>GeV</mml:mi></mml:mrow></mml:math> . The data are compared to predictions from perturbative QCD in next-to-leading order in the strong coupling, in approximate next-to-next-to-leading order and in full next-to-next-to-leading order. Using also the recently published H1 jet data at high values of $$Q^2$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msup><mml:mi>Q</mml:mi><mml:mn>2</mml:mn></mml:msup></mml:math> , the strong coupling constant $$\alpha _s(M_Z)$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msub><mml:mi>α</mml:mi><mml:mi>s</mml:mi></mml:msub><mml:mrow><mml:mo>(</mml:mo><mml:msub><mml:mi>M</mml:mi><mml:mi>Z</mml:mi></mml:msub><mml:mo>)</mml:mo></mml:mrow></mml:mrow></mml:math> is determined in next-to-leading order.

In $e^+ e^-$ collisions, electromagnetic effects caused by large charge density bunches modify the effective acceptance of the luminometer system of the experiments. These effects consequently bias the luminosity measurement from the rate of low-angle Bhabha interactions $e^+ e^- \to e^+ e^- $. Surprisingly enough, the magnitude of this bias is found to yield an underestimation of the integrated luminosity measured by the LEP experiments by about 0.1%, significantly larger than the reported experimental uncertainties. When accounted for, this effect modifies the number of light neutrino species determined at LEP from the measurement of the hadronic cross section at the Z peak.

Potato (Solanum tuberosum L.) is a crop of great importance worldwide due to its high nutritional value and its adaptability to different climatic conditions. In Peru, it is one of the main crops in terms of production and consumption, with Junín being one of the departments with the highest production. The aim of this research was to evaluate the effect of water stress on the growth and yield of commercial potato cultivars. Four irrigation frequencies (field capacity, every 7, 14 and 21 days) and five commercial potato cultivars (Canchán, Yungay, Wankita, Serranita and Shulay) were evaluated, distributed in a completely randomized design with a 5x4 factorial arrangement, with five replications. It was installed under greenhouse conditions and seven variables (plant emergence, plant height, number of stems, number and weight of tubers, transpiration rate and dry matter) were evaluated. The results showed statistical differences in all the variables evaluated. It was found that the Canchán cultivar with irrigation frequency every 21 days was more tolerant to drought with an average rate of 0.69 ml, the maximum permissible irrigation limit in greenhouse is every 14 days. The highest number of tubers was observed in the Wankita cultivar with 29.8 tubers under a drought stress of 14 days. The highest tuber weight was obtained with the Yungay cultivar at field capacity with 0.438 kg per plant. It is concluded that water stress influences potato growth and production.

A first measurement is presented of exclusive photoproduction of $$\rho ^0$$ mesons associated with leading neutrons at HERA. The data were taken with the H1 detector in the years 2006 and 2007 at a centre-of-mass energy of $$\sqrt{s}=319$$ GeV and correspond to an integrated luminosity of 1.16 pb $$^{-1}$$ . The $$\rho ^0$$ mesons with transverse momenta $$p_T<1$$ GeV are reconstructed from their decays to charged pions, while leading neutrons carrying a large fraction of the incoming proton momentum, $$x_L>0.35$$ , are detected in the Forward Neutron Calorimeter. The phase space of the measurement is defined by the photon virtuality $$Q^2 < 2$$ GeV $$^2$$ , the total energy of the photon–proton system $$20 < W_{\gamma p}< 100$$ GeV and the polar angle of the leading neutron $$\theta _n < 0.75$$ mrad. The cross section of the reaction $$\gamma p \rightarrow \rho ^0 n \pi ^+$$ is measured as a function of several variables. The data are interpreted in terms of a double peripheral process, involving pion exchange at the proton vertex followed by elastic photoproduction of a $$\rho ^0$$ meson on the virtual pion. In the framework of one-pion-exchange dominance the elastic cross section of photon-pion scattering, $$\sigma ^\mathrm{el}(\gamma \pi ^+ \rightarrow \rho ^0\pi ^+)$$ , is extracted. The value of this cross section indicates significant absorptive corrections for the exclusive reaction $$\gamma p \rightarrow \rho ^0 n \pi ^+$$ .

We show that the angle $\alpha_{ds}$ of the ``flattest'' unitarity triange can be directly measured using the decays $\overline{B}_{d}\to \phi \overline{K}^{(*)0}$ and $\overline{B}_{s}\to \phi{K}^{(*)0}$. Using both $\overline{B}_{d}$ and $\overline{B}_{s}$ enables a further consistency test since the expected time-dependent CP violating asymmetries are identical though with opposite signs. Since large statistics of $\overline{B}_{d}$ and $\overline{B}_{s}$ are needed for accurate measurements, FCC-ee and its environment at the Z-pole is well suited for such studies. These measurements, the precision of which could reach the sub-degree level, will contribute to probe further the consistency of the CP sector of the Standard Model with unprecedented level of accuracy. The main detector requirements that are set by these measurements are also outlined.

The de Haas--van Alphen oscillation spectrum is studied for an idealized two-dimensional Fermi liquid with two parabolic bands in the case of canonical (fixed number of quasiparticles) and grand canonical (fixed chemical potential) ensembles. As already reported in the literature, oscillations of the chemical potential in magnetic field yield frequency combinations that are forbidden in the framework of the semiclassical theory. Exact analytical calculation of the Fourier components is derived at zero temperature, and an asymptotic expansion is given for the high-temperature and low-magnetic-field range. Good agreement is obtained between analytical formulas and numerical computations.

The work contained herein constitutes a report of the ``Beyond the Standard Model'' working group for the Workshop "Physics at TeV Colliders", Les Houches, France, 26 May--6 June, 2003. The research presented is original, and was performed specifically for the workshop. Tools for calculations in the minimal supersymmetric standard model are presented, including a comparison of the dark matter relic density predicted by public codes. Reconstruction of supersymmetric particle masses at the LHC and a future linear collider facility is examined. Less orthodox supersymmetric signals such as non-pointing photons and R-parity violating signals are studied. Features of extra dimensional models are examined next, including measurement strategies for radions and Higgs', as well as the virtual effects of Kaluza Klein modes of gluons. An LHC search strategy for a heavy top found in many little Higgs model is presented and finally, there is an update on LHC $Z'$ studies.

This note gives a conceptual description and illustration of the CLD detector, based on the work for a detector at CLIC. CLD is one of the detectors envisaged at a future 100 km $e^+e^-$ circular collider (FCC-ee). The note also contains a brief description of the simulation and reconstruction tools used in the linear collider community, which have been adapted for physics and performance studies of CLD. The detector performance is described in terms of single particles, particles in jets, jet energy and angular resolution, and flavour tagging. The impact of beam-related backgrounds (incoherent $e^+e^-$ pairs and synchrotron radiation photons) on the performance is also discussed.

The parameters of the electroweak theory are determined in a combined electroweak and QCD analysis using all deep-inelastic $$e^+p$$ and $$e^-p$$ neutral current and charged current scattering cross sections published by the H1 Collaboration, including data with longitudinally polarised lepton beams. Various fits to Standard Model parameters in the on-shell scheme are performed. The mass of the W boson is determined as $$m_W=80.520\pm 0.115~\mathrm {GeV} $$ . The axial-vector and vector couplings of the light quarks to the Z boson are also determined. Both results improve the precision of previous H1 determinations based on HERA-I data by about a factor of two. Possible scale dependence of the weak coupling parameters in both neutral and charged current interactions beyond the Standard Model is also studied. All results are found to be consistent with the Standard Model expectations.

The strong coupling constant $\alpha_s(M_Z)$ is determined from inclusive jet and dijet cross sections in neutral-current deep-inelastic $ep$ scattering (DIS) measured at HERA by the H1 collaboration using next-to-next-to-leading order (NNLO) QCD predictions. The dependence of the NNLO predictions and of the resulting value of $\alpha_s(M_Z)$ at the $Z$-boson mass $m_Z$ are studied as a function of the choice of the renormalisation and factorisation scales. Using inclusive jet and dijet data together, the strong coupling constant is determined to be $\alpha_s(M_Z)=0.1166\,(19)_{\rm exp}\,(24)_{\rm th}$. Complementary, $\alpha_s(M_Z)$ is determined together with parton distribution functions of the proton (PDFs) from jet and inclusive DIS data measured by the H1 experiment. The value $\alpha_s(M_Z)=0.1147\,(25)_{\rm tot}$ obtained is consistent with the determination from jet data alone. The impact of the jet data on the PDFs is studied. The running of the strong coupling is tested at different values of the renormalisation scale and the results are found to be in agreement with expectations.

This document answers in simple terms many FAQs about FCC-ee, including comparisons with other colliders. It complements the FCC-ee CDR and the FCC Physics CDR by addressing many questions from non-experts and clarifying issues raised during the European Strategy symposium in Granada, with a view to informing discussions in the period between now and the final endorsement by the CERN Council in 2020 of the European Strategy Group recommendations. This document will be regularly updated as more questions appear or new information becomes available.

The first stage of the FCC (Future Circular Collider) is a high-luminosity electron-positron collider (FCC-ee) with centre-of-mass energy ranging from 88 to 365 GeV, to study with high precision the Z, W, Higgs and top particles, with samples of $5 \times 10^{12}$ Z bosons, $10^8$ W pairs, $10^6$ Higgs bosons and $10^6$ top quark pairs. A cornerstone of the physics program lays in the precise (ppm) measurements of the W and Z masses and widths, as well as forward-backward asymmetries. To this effect the centre-of-mass energy distribution should be determined with the high precision. This document describes the capacity offered by FCC-ee, starting with transverse polarization of the beams around the Z pole and the W pair threshold. A running scheme based on regular measurements of the beam energy by resonant depolarization of pilot bunches, during physics data taking, is proposed. The design for polarization wigglers, polarimeter and depolarizer is outlined. The $e^\pm$ beam energies will be monitored with a relative precision of $10^{-6}$. The centre-of-mass energy is derived subject to further corrections, related to the beam acceleration, synchrotron radiation and beamstrahlung; these effects are identified and evaluated. Dimuon events $e^+e^- \to \mu^+ \mu^-$, recorded in the detectors, provide with great precision the beam crossing angle, the centre-of-mass energy spread, and the $e^+$ and $e^-$ energy difference. Monitoring methods to minimize absolute error and relative uncertainties are discussed. The impact on the physics measurements is given. A programme of further simulations, design, monitoring and R&D is outlined.

The first part of the physics programme of the integrated FCC (Future Circular Colliders) proposal includes measurements of Standard Model processes in $e^+e^-$ collisions (FCC-ee) with an unprecedented precision. In particular, the potential precision of the Z lineshape determination calls for a very precise measurement of the absolute luminosity, at the level of 1E-4, and the precision on the relative luminosity between energy scan points around the Z pole should be an order of magnitude better. The luminosity is principally determined from the rate of low-angle Bhabha interactions, $e^+e^- \to e^+e^-$, where the final state electrons and positrons are detected in dedicated calorimeters covering small angles from the outgoing beam directions. Electromagnetic effects caused by the very large charge density of the beam bunches affect the effective acceptance of these luminometers in a nontrivial way. If not corrected for, these effects would lead, at the Z pole, to a systematic bias of the measured luminosity that is more than one order of magnitude larger than the desired precision. In this note, these effects are studied in detail, and methods to measure and correct for them are proposed.

The first stage of the FCC (Future Circular Collider) is a high-luminosity electron-positron collider (FCC-ee) with centre-of-mass energy ranging from 88 to 365 GeV, to study with high precision the Z, W, Higgs and top particles, with samples of $5 \times 10^{12}$ Z bosons, $10^8$ W pairs, $10^6$ Higgs bosons and $10^6$ top quark pairs. A cornerstone of the physics program lays in the precise (ppm) measurements of the W and Z masses and widths, as well as forward-backward asymmetries. To this effect the centre-of-mass energy distribution should be determined with the high precision. This document describes the capacity offered by FCC-ee, starting with transverse polarization of the beams around the Z pole and the W pair threshold. A running scheme based on regular measurements of the beam energy by resonant depolarization of pilot bunches, during physics data taking, is proposed. The design for polarization wigglers, polarimeter and depolarizer is outlined. The $e^\pm$ beam energies will be monitored with a relative precision of $10^{-6}$. The centre-of-mass energy is derived subject to further corrections, related to the beam acceleration, synchrotron radiation and beamstrahlung; these effects are identified and evaluated. Dimuon events $e^+e^- \to \mu^+ \mu^-$, recorded in the detectors, provide with great precision the beam crossing angle, the centre-of-mass energy spread, and the $e^+$ and $e^-$ energy difference. Monitoring methods to minimize absolute error and relative uncertainties are discussed. The impact on the physics measurements is given. A programme of further simulations, design, monitoring and R&D is outlined.

The FCC-ee offers powerful opportunities to determine the Higgs boson parameters, exploiting over $10^6$ ${\rm e^+e^- \to ZH}$ events and almost $10^5$ ${\rm WW \to H}$ events at centre-of-mass energies around 240 and 365 GeV. This essay spotlights the important measurements of the ZH production cross section and of the Higgs boson mass. The measurement of the total ZH cross section is an essential input to the absolute determination of the HZZ coupling -- a "standard candle" that can be used by all other measurements, including those made at hadron colliders -- at the per-mil level. A combination of the measured cross sections at the two different centre-of-mass energies further provides the first evidence for the trilinear Higgs self-coupling, and possibly its first observation if the cross-section measurement can be made accurate enough. The determination of the Higgs boson mass with a precision significantly better than the Higgs boson width (4.1 MeV in the Standard Model) is a prerequisite to either constrain or measure the electron Yukawa coupling via direct ${\rm e^+e^- \to H}$ production at $\sqrt{s} = 125$ GeV. Approaching the statistical limit of 0.1% and $\mathcal{O}(1)$ MeV on the ZH cross section and the Higgs boson mass, respectively, sets highly demanding requirements on accelerator operation (ZH threshold scan, centre-of-mass energy measurement), detector design (lepton momentum resolution, hadronic final state reconstruction performance), theoretical calculations, and analysis techniques (efficiency and purity optimization with modern tools, constrained kinematic fits, control of systematic uncertainties). These challenges are examined in turn in this essay.

Hadronic response and electron identification performance of the new H1 lead-scintillating fibre calorimeter are investigated in the 1 to 7 GeV energy range using data taken at the CERN Proton Synchrotron. The energy response to minimum ionizing particles and interacting pions are studied and compared to Monte Carlo simulations. The measured energy of pions interacting either in the electromagnetic or in the hadronic section is found to scale linearly with the incident energy, providing an energy resolution σE ∼ 38% within a depth of one interaction length and σE ∼ 29% for a total depth of two interaction lengths. Several electron identification estimators are studied and combined as a function of energy and impact point. The probability for pions to be misidentified as electrons of any measured energy above 1 GeV ranges from 5% (for 2 GeV incident pions) to 0.4% (at 7 GeV) for an electron detection efficiency of 90%. The probability for pions of a given energy to be misidentified as electrons of the same energy falls to 0.25% at 7 GeV.

The international Future Circular Collider (FCC) study aims at a design of $pp$, $e^+e^-$, $ep$ colliders to be built in a new 100 km tunnel in the Geneva region. The $e^+e^-$ collider (FCC-ee) has a centre of mass energy range between 90 (Z-pole) and 375 GeV (tt_bar). To reach such unprecedented energies and luminosities, the design of the interaction region is crucial. The crab-waist collision scheme has been chosen for the design and it will be compatible with all beam energies. In this paper we will describe the machine detector interface layout including the solenoid compensation scheme. We will describe how this layout fulfills all the requirements set by the parameters table and by the physical constraints. We will summarize the studies of the impact of the synchrotron radiation, the analysis of trapped modes and of the backgrounds induced by single beam and luminosity effects giving an estimate of the losses in the interaction region and in the detector.

Measurements of $$D^{*}(2010)$$ meson production in diffractive deep inelastic scattering $$(5<Q^{2}<100\,\mathrm{GeV}^{2})$$ are presented which are based on HERA data recorded at a centre-of-mass energy $$\sqrt{s} = 319\,\mathrm{GeV}$$ with an integrated luminosity of 287 pb $$^{-1}$$ . The reaction $$ep \rightarrow eXY$$ is studied, where the system X, containing at least one $$D^{*}(2010)$$ meson, is separated from a leading low-mass proton dissociative system Y by a large rapidity gap. The kinematics of $$D^{*}$$ candidates are reconstructed in the $$D^{*}\rightarrow K \pi \pi $$ decay channel. The measured cross sections compare favourably with next-to-leading order QCD predictions, where charm quarks are produced via boson-gluon fusion. The charm quarks are then independently fragmented to the $$D^{*}$$ mesons. The calculations rely on the collinear factorisation theorem and are based on diffractive parton densities previously obtained by H1 from fits to inclusive diffractive cross sections. The data are further used to determine the diffractive to inclusive $$D^{*}$$ production ratio in deep inelastic scattering.

The use of accelerator driven system (ADS) like for instance the Energy Amplifier concept (EA) proposed by C. Rubbia and his group might be one of the solutions to solve the energy problem and in particular to answer the question: what could we do with the nuclear waste produced by the present nuclear reactors? We present in this paper the EA concept, which is illustrated by two experiments performed at the CERN-PS facility. One of them is the TARC (Transmutation by Adiabatic Resonance crossing) experiment which is designed to demonstrate the high efficiency offered by the EA to destroy the long-lived fission fragments.

In aeronautics and in off-shore petroleum industries, the development of a DC (Direct Current) distribution at high voltage is necessary, in order to improve the systems operational performances, whether for aircrafts or pipe-lines for petroleum distribution. Such voltages may lead to phenomena of charge injection and accumulation in the electric systems insulation, also known as space charge. It can generate an electric field amplification, in the dielectric bulk or near the conductors, which in turn can trigger accelerated aging phenomena and premature failures. With the use of new materials, it is necessary to assess whether the space charge has a significant impact for the dielectrics of interest, and should be taken into account in the insulation sizing. This paper presents several ways to evaluate the phenomenon, and presents experimental results on Silicone, Epoxy and Fluoropolymers, in the range between 23°C and 200°C. As a perspective, the impact of space charge on the material aging is also discussed.

The FCC-ee machine induced backgrounds on the two proposed detectors (CLD and IDEA) have been studied in detail. Synchrotron Radiation (SR) considerations dictate the Interaction Region (IR) optimization. An asymmetric IR design limits the final bend critical energy to 100 keV. Masks placed before the final focus quadrupole protect the detector from direct hits, and a shield placed around the beam pipe from secondary particles, keeping the effect of SR on the detector to negligible levels. The most important source of background is expected to be the Incoherent Pair Creation (IPC). Its effect has been studied in full simulation and reconstruction, and it was shown that it will not pose a problem for the detector, even if conservative estimations for the time resolution of the detector sensors are assumed. Moreover, the [Formula: see text], radiative Bhabhas and beam-gas interaction induced backgrounds were studied. All were found to have small to negligible effect on the detector. Overall, the FCC–ee interaction region backgrounds are not expected to compromise the detector performance.

The FCC-ee offers powerful opportunities to determine the Higgs boson parameters, exploiting over $10^6$${\rm e^+e^- \to ZH}$ events and almost $10^5$${\rm WW \to H}$ events at centre-of-mass energies around 240 and 365 GeV. The measurement of the total ZH cross section is an essential input to the absolute determination of the HZZ coupling -- a ``standard candle'' that can be used by all other measurements, including those made at hadron colliders -- at the per-mil level. A combination of the measured cross sections at the two different centre-of-mass energies further provides the first evidence for the trilinear Higgs self-coupling, and possibly its first observation if the cross-section measurement can be made accurate enough. The determination of the Higgs boson mass with a precision significantly better than the Higgs boson width (4.1 MeV in the Standard Model) is a prerequisite to either constrain or measure the electron Yukawa coupling via direct ${\rm e^+e^- \to H}$ production at $\sqrt{s} = 125$ GeV. Approaching the statistical limit of 0.1% and $\mathcal{O}(1)$ MeV on the ZH cross section and the Higgs boson mass, respectively, sets highly demanding requirements on accelerator operation (ZH threshold scan, centre-of-mass energy measurement), detector design (lepton momentum resolution, hadronic final state reconstruction performance), theoretical calculations (higher-order corrections to the cross section), and analysis techniques (efficiency and purity optimization with modern tools, constrained kinematic fits, control of systematic uncertainties). These challenges are examined in turn in this essay.

Abstract Circular colliders have the advantage of delivering collisions to multiple interaction points, which allow different detector designs to be studied and optimised—up to four for FCC-ee. On the one hand, the detectors must satisfy the constraints imposed by the invasive interaction region layout. On the other hand, the performance of heavy-flavour tagging, of particle identification, of tracking and particle-flow reconstruction, and of lepton, jet, missing energy and angular resolution, need to match the physics programme and the exquisite statistical precision offered by FCC-ee. During the FCC feasibility study (2021–2025), benchmark physics processes will be used to determine, via appropriate simulations, the requirements on the detector performance or design that must be satisfied to ensure that the systematic uncertainties of the measurements are commensurate with their statistical precision. The usage of the data themselves, in order to reach the challenging goals on the stability and on the alignment of the detector, in particular for the programme at and around the Z peak, will also be studied. In addition, the potential for discovering very weakly coupled new particles, in decays of Z or Higgs bosons, could motivate dedicated detector designs that would increase the efficiency for reconstructing the unusual signatures of such processes. These studies are crucial input to the further optimisation of the two concepts described in the FCC-ee conceptual design report, CLD and IDEA, and to the development of new concepts which might actually prove to be better adapted to the FCC-ee physics programme, or parts thereof.

Many theoretical models, like the Standard Model or SUSY at large tan(β), predict Higgs bosons or new particleswhich decay more abundantly to final states including tau leptons than to other leptons. At the energy scale of theLHC, the identification of tau leptons, in particular in the hadronic decay mode, will be a challenging task due to anoverwhelming QCD background which gives rise to jets of particles that can be hard to distinguish from hadronic taudecays. Equipped with excellent tracking and calorimetry, the ATLAS experiment has developed tau identificationtools capable of working at the trigger level. This contribution presents tau trigger algorithms which exploit the mainfeatures of hadronic tau decays and describes the current tau trigger commissioning activities.

We investigate the sensitivity with which two angles of the flat unitarity triangle, defined by ${V}_{ub}^{*}{V}_{us}+{V}_{cb}^{*}{V}_{cs}+{V}_{tb}^{*}{V}_{ts}=0$, can possibly be measured directly at FCC-ee. We show that the measured errors on the angle ${\ensuremath{\alpha}}_{s}=\mathrm{arg}(\ensuremath{-}{V}_{ub}^{*}{V}_{us}/{V}_{tb}^{*}{V}_{ts})$ and ${\ensuremath{\beta}}_{s}=\mathrm{arg}(\ensuremath{-}{V}_{tb}^{*}{V}_{ts}/{V}_{cb}^{*}{V}_{cs})$ should be better than 0.4\ifmmode^\circ\else\textdegree\fi{} and 0.035\ifmmode^\circ\else\textdegree\fi{}, respectively. These measurements, combined with the measurement of the third angle ${\ensuremath{\gamma}}_{s}=\mathrm{arg}(\ensuremath{-}{V}_{cb}^{*}{V}_{cs}/{V}_{ub}^{*}{V}_{us})$, discussed in a different paper, will contribute to probing the consistency of the $CP$ sector of the Standard Model further with an unprecedented level of accuracy.

Many theoretical models, like the Standard Model or SUSY at large tan(beta), predict Higgs bosons or new particles which decay more abundantly to final states including tau leptons than to other leptons. At the energy scale of the LHC, the identification of tau leptons, in particular in the hadronic decay mode, will be a challenging task due to an overwhelming QCD background which gives rise to jets of particles that can be hard to distinguish from hadronic tau decays. Equipped with excellent tracking and calorimetry, the ATLAS experiment has developed tau identification tools capable of working at the trigger level. This contribution presents tau trigger algorithms which exploit the main features of hadronic tau decays and describes the current tau trigger commissioning activities.

Circular colliders have the advantage of delivering collisions to multiple interaction points, which allow different detector designs to be studied and optimized - up to four for FCC-ee. On the one hand, the detectors must satisfy the constraints imposed by the invasive interaction region layout. On the other hand, the performance of heavy-flavour tagging, of particle identification, of tracking and particle-flow reconstruction, and of lepton, jet, missing energy and angular resolution, need to match the physics programme and the exquisite statistical precision offered by FCC-ee. During the FCC feasibility study (2021-2025), benchmark physics processes will be used to determine, via appropriate simulations, the requirements on the detector performance or design that must be satisfied to ensure that the systematic uncertainties of the measurements are commensurate with their statistical precision. The usage of the data themselves, in order to reach the challenging goals on the stability and on the alignment of the detector, in particular for the programme at and around the Z peak, will also be studied. In addition, the potential for discovering very weakly coupled new particles, in decays of Z or Higgs bosons, could motivate dedicated detector designs that would increase the efficiency for reconstructing the unusual signatures of such processes. These studies are a crucial input to the further optimization of the two concepts described in the Conceptual Design Report, CLD, and IDEA, and to the development of new concepts which might actually prove to be better adapted to the FCC-ee physics programme, or parts thereof.

Exact analytical results of the de Haas–van Alphen (dHvA) effect in an idealized two-band Fermi liquid with parabolic dispersion are presented. We consider a Fermi surface consisting in two electron bands with different band edges and band masses. Magnetic breakthrough between the bands is negligible. Analytical expressions of the dHvA Fourier amplitudes are derived in the case where the total number of electron is fixed (Canonical Ensemble). As already reported in the literature, the oscillations of the chemical potential yield frequency mixing and Lifshitz–Kosevich theory, which is valid in the Grand Canonical Ensemble, does not apply at very low temperature. We show that the corresponding Fourier amplitudes depend on the commensurability between the two effective masses and also the two fundamental frequencies.

An overview of recent experimental results on searches for new phenomena at the LEP, HERA and Tevatron high energy colliders is presented, including in particular new results obtained from the analysis of the Run II data at the Tevatron. No significant evidence for physics beyond the Standard Model has been found and limits at the 95% confidence level have been set on the mass and couplings of several new particles. The complementarity between the different experiments is discussed, as well as future prospects for ongoing and future experiments.

Triggering on hadronic taus at the LHC is a difficult task due to the high rate and occupancy of the events. On the other hand, the tau trigger increases the discovery potential of ATLAS in many physics channels, among others the Standard Model or SuperSymmetric Higgs (charged or neutrals) production. In order to cope with the rate and optimize the efficiency on important physics channels, the results of the current simulation studies indicate that the ATLAS tau trigger should be used either with relatively high transverse momentum thresholds alone, or with more relaxed threshold requirements in combination with other triggers, like the missing transverse energy trigger or a leptonic or jet trigger. In this contribution we describe the ATLAS tau trigger, and we present some of the current results from the simulation studies, focusing both on early physics and on physics at high luminosity.

Les biopuces sont des outils d'analyse et de diagnostic de plus en plus utilises dans le domaine medical et celui de la securite. Les puces a proteines sont particulierement interessantes car les proteines sont les manifestations directes de l'activite cellulaire. Ces puces sont generalement constituees d'un support sur lequel sont deposes des sondes possedant une affinite particuliere avec les cibles a detecter. Cependant, leur selectivite et sensibilite n'est parfois pas suffisante pour detecter de maniere fiable les concentrations letales des certaines toxines, en particulier a cause de l'adsorption non specifique des cibles sur la surface et de le fragilite de la chimie d'immobilisation des sondes. Cette these s'est attelee a ameliorer ces parametres en proposant une chimie controlee sur silicium qui, en utilisant des molecules composees d'un alcene et d'une chaine poly(ethylene glycol), a permis de tres largement limiter cette adsorption indesirable, tandis que la presence d'un groupement acide carboxylique en surface a permis l'immobilisation covalente des sondes aptameres capables de reconnaitre des proteines.

This dissertation works is an a comparative study who, based on faith as a paradigm, put in dialogue two works and two authors historically distant from each other but near to other levels of sense, namely, Las moradas by Teresa de Jesus y A maca no escuro by Clarice Lispector. As a result, beyond to suggest just an analysis compared textual, goes to the philosophical, theological and historical bases possible and latent in both works, and in the lives and contexts of their respective authors whit the purpose of explain gradually similarities and differences put in tension.

In the TARC experiment the differential neutron flux φ(E,r⃗) of a spallation of 2.5 and 3.5 GeV/c proton in large lead block is measured in the range between 0.1 eV and 1.5 MeV. A new technique, using small quantities (less than 0.1 gram) of material, is used for measuring the transmutation rate as a function of neutron energy in the range between 0.1 eV up to a few keV. The method is applied to a target of 86 mg (99Tc) mixed with 1.7 g of Aluminum. From these measurements the energy profile of the capture cross section can be extracted.

With increasing Tevatron luminosity, efficient triggers that meet the bandwidth limitations of the experiment's data acquisition system become more and more difficult to construct. To meet these challenges, the DOslash experiment has significantly enhanced its triggering capabilities. A major component of this upgrade is a completely re-designed Level-1 calorimeter trigger (L1Cal). This new system uses novel architecture and algorithms to maintain acceptable background rejection while preserving or even improving signal efficiency at the highest luminosities foreseen. We describe interesting features of the L1Cal and give highlights from its first few months of operation.

We present a measurement of the cross section for $Z$ production times the branching fraction to $\tau$ leptons, $\sigma \cdot$Br$(Z\to \tau^+ \tau^-)$, in $p \bar p$ collisions at $\sqrt{s}=$1.96 TeV in the channel in which one $\tau$ decays into $\mu \nu_{\mu} \nu_{\tau}$, and the other into $\rm {hadrons} + \nu_{\tau}$ or $e \nu_e \nu_{\tau}$. The data sample corresponds to an integrated luminosity of 226 pb$^{-1}$ collected with the D{\O}detector at the Fermilab Tevatron collider. The final sample contains 2008 candidate events with an estimated background of 55%. From this we obtain $\sigma \cdot$Br$(Z \to \tau^+ \tau^-)=237 \pm 15$(stat)$\pm 18$(sys)$ \pm 15$(lum) pb, in agreement with the standard model prediction.

We investigate the sensitivity with which two angles of the flat unitarity triangle, defined by $V_{ub}^* V_{us} + V_{cb}^* V_{cs} + V_{tb}^* V_{ts} =0$, can possibly be measured directly at FCCee. We show that the measured errors on the angle $\alpha_s = \arg(- V_{ub}^* V_{us} /V_{tb}^* V_{ts})$ and $\beta_s = \arg(-V_{tb}^* V_{ts} / V_{cb}^* V_{cs})$ should be better than $0.4^\circ$ and $0.035^\circ$, respectively. These measurements, combined with the measurement of the 3rd angle $\gamma_s = \arg(- V_{cb}^* V_{cs}/ V_{ub}^* V_{us})$, discussed in a different paper, will contribute to probe further the consistency of the CP sector of the Standard Model with unprecedented level of accuracy.

The great progress made recently in the sector of Flavor Physics has enabled to establish CP violation in the B-meson decays. The unitarity triangle derived from the unitarity relation $V_{ub}^* V_{ud} + V_{cb}^* V_{cd} + V_{tb}^* V_{td} = 0$ has been measured very precisely. To further asses our understanding of CP violation, it would be useful to carry out similar measurement of other triangles. In this note, we investigate the triangle derived from the relation $V_{ub}^* V_{us} + V_{cb}^* V_{cs} + V_{tb}^* V_{ts} = 0$. Two angles of this triangle ($\alpha_s$ and $\beta_s$) could be measured very accurately at FCCee using the decays $B_s(\overline{B_s})\rightarrow D^\pm_sK^\mp$ and $B_s(\overline{B_s})\rightarrow J/\psi \phi$ respectively, as discussed elsewhere by us. This note concentrates on the measurement of the third angle $\gamma_s$ using the modes $B^\pm \to \overline{D^0}(D^0)K^\pm$. We show that a direct measurement of the angle $\gamma_s$ is possible with some specific $B^\pm$ decays with an estimated resolution of the order of 1$^\circ$.

Circular colliders have the advantage of delivering collisions to multiple interaction points, which allow different detector designs to be studied and optimized - up to four for FCC-ee. On the one hand, the detectors must satisfy the constraints imposed by the invasive interaction region layout. On the other hand, the performance of heavy-flavour tagging, of particle identification, of tracking and particle-flow reconstruction, and of lepton, jet, missing energy and angular resolution, need to match the physics programme and the exquisite statistical precision offered by FCC-ee. During the FCC feasibility study (2021-2025), benchmark physics processes will be used to determine, via appropriate simulations, the requirements on the detector performance or design that must be satisfied to ensure that the systematic uncertainties of the measurements are commensurate with their statistical precision. The usage of the data themselves, in order to reach the challenging goals on the stability and on the alignment of the detector, in particular for the programme at and around the Z peak, will also be studied. In addition, the potential for discovering very weakly coupled new particles, in decays of Z or Higgs bosons, could motivate dedicated detector designs that would increase the efficiency for reconstructing the unusual signatures of such processes. These studies are a crucial input to the further optimization of the two concepts described in the Conceptual Design Report, CLD, and IDEA, and to the development of new concepts which might actually prove to be better adapted to the FCC-ee physics programme, or parts thereof.

In this work the effets of fragmentation process on shaped charge jet penetration have been examined by means of X Ray cinematography (6 tubes). Visualizations of the emerging jet after target perforation show that : - the maximum penetration is produced by a completely fragmented jet - even at very little standoff an important part of the total penetration is produced by jet fragments - if the jet fragments are well aligned, the penetration process is not affected by the distance seperating them.

Searches for contact interactions, leptoquark bosons and excited fermions carried out at the HERA ep collider are presented here. The searches are based on ~ 40 pb^-1 of e+ p data per experiment collected at a centre of mass energy ~ 300 GeV. First results on e- p data collected in 1998-1999 are also presented.