Francesca Romana Cavallo

We have studied the energy-energy angular correlations in hadronic final states from Z0 decay using the DELPHI detector at LEP. From a comparison with Monte Carlo calculations based on the exact second order QCD matrix element and string fragmentation we find that Λ(5)MS=104+25-20(stat.)+25-20(syst.)+3000)theor.). MeV, which corresponds to αs(91 GeV)=0.106±0.003(stat.)±0.003(syst.)+0.003-0.000(theor). The theoretical error stems from different choices for the renormalization scale of αs. In the Monte Carlo simulation the scale of αs as well as the fragmentation parameters have been optimized to described reasonably well all aspects of multihadron production.

A sample of 2.2 million hadronic Z decays, selected from the data recorded by the Delphi detector at Lep during 1994–1995 was used for an improved measurement of inclusive distributions of $\pi^+, K^+$ and p and their antiparticles in gluon and quark jets. The production spectra of the individual identified particles were found to be softer in gluon jets compared to quark jets, with a higher multiplicity in gluon jets as observed for inclusive charged particles. A significant proton enhancement in gluon jets is observed indicating that baryon production proceeds directly from colour objects. The maxima, $\xi^*$ , of the $\xi$ -distributions for kaons in gluon and quark jets are observed to be different.

The Compact Muon Solenoid (CMS) experiment prepares its Phase-2 upgrade for the high-luminosity era of the LHC operation (HL-LHC). Due to the increase of occupancy, trigger latency and rates, the full electronics of the CMS Drift Tube (DT) chambers will need to be replaced. In the new design, the time bin for the digitization of the chamber signals will be of around 1 ns, and the totality of the signals will be forwarded asynchronously to the service cavern at full resolution. The new backend system will be in charge of building the trigger primitives of each chamber. These trigger primitives contain the information at chamber level about the muon candidates position, direction, and collision time, and are used as input in the L1 CMS trigger. The added functionalities will improve the robustness of the system against ageing. An algorithm based on analytical solutions for reconstructing the DT trigger primitives, called Analytical Method, has been implemented both as a software C++ emulator and in firmware. Its performance has been estimated using the software emulator with simulated and real data samples, and through hardware implementation tests. Measured efficiencies are 96 to 98% for all qualities and time and spatial resolutions are close to the ultimate performance of the DT chambers. A prototype chain of the HL-LHC electronics using the Analytical Method for trigger primitive generation has been installed during Long Shutdown 2 of the LHC and operated in CMS cosmic data taking campaigns in 2020 and 2021. Results from this validation step, the so-called Slice Test, are presented.

From the analysis of a data sample corresponding to an integrated luminosity of 4.63 pb−1 taken during the 1990 run of LEP at centre of mass energies between 88.2 GeV an 94.2 GeV, the tau decays $$\tau ^ - \to e^ - \bar v_e v_\tau ,\tau ^ - \to \mu ^ - \bar v_\mu v_\tau ,\tau ^ - \to \pi ^ - (K^ - )v_\tau ,\tau ^ - \to \rho {}^ - v_\tau $$ and their charge conjugates have been studied. The following branching ratios have been measured; $$BR(\tau ^ - \to e^ - \bar v_e v_\tau ) = 18.6 \pm 0.8(stat.) \pm 0.6(sys.)\% ,$$ , $$BR\left( {\tau ^ - \to \mu ^ - \bar v_\mu v_\tau } \right) = 17.4 \pm 0.7 \pm 0.6\% ,$$ , Br(τ− → π− (K−)vτ)=11.9±0.7±0.7%, BR (τ− → ρ− vτ)= 22.4±0.8±1.3%, in good agreement with world averages. The measured electronic and muonic branching ratios lead to a measurement of the strong coupling constant, αs (mτ) = 0.26 −0.12 +0.09 . Extrapolating the αs value fromm τ tom Z yields αs (mZ) = 0.109 −0.028 +0.012 . The average polarizationP τ of taus produced in Z → τs τs decays has also been measured using the above decay modes. The weighted mean of the polarizations obtained from the four decay modes isP τ=−0.24±0.07. This value ofP τ gives, in the improved Born approximation, a ratio between the axial and vector coupling constants of the tau of υτ/aτ = 0.12 ± 0.04, and hence a value of the effective electroweak mixing parameter sin2 θW(m Z 2 ).

The 40 MHz bunched muon beam set up at CERN was used in May 2003 to make a full test of the drift tubes local muon trigger. The main goal of the test was to prove that the integration of the various devices located on a muon chamber was adequately done both on the hardware and software side of the system. Furthermore the test provided complete information about the general performance of the trigger algorithms in terms of efficiency and noise. Data were collected with the default configuration of the trigger devices and with several alternative configurations at various angles of incidence of the beam. Tests on noise suppression and di-muon trigger capability were performed.

This contribution introduces a new type of Micropattern Gaseous Detector, the Fast Timing Micropattern (FTM) detector, utilizing fully Resistive WELL structures. The structure of the prototype will be described in detail and the results of the characterization study performed with an X-ray gun will be presented, together with the first results on time resolution based on data collected with muon/pion test beams.

Gas Electron Multipliers (GEM) are a proven position sensitive gas detector technology which nowadays is becoming more widely used in High Energy Physics. GEMs offer an excellent spatial resolution and a high particle rate capability, with a close to 100% detection efficiency. In view of the high luminosity phase of the CERN Large Hadron Collider, these aforementioned features make GEMs suitable candidates for the future upgrades of the Compact Muon Solenoid (CMS) detector. In particular, the CMS GEM Collaboration proposes to cover the high-eta region of the muon system with large-area triple-GEM detectors, which have the ability to provide robust and redundant tracking and triggering functions. In this contribution, after a general introduction and overview of the project, the construction of full-size trapezoidal triple-GEM prototypes will be described in more detail. The procedures for the quality control of the GEM foils, including gain uniformity measurements with an x-ray source will be presented. In the past few years, several CMS triple-GEM prototype detectors were operated with test beams at the CERN SPS. The results of these test beam campaigns will be summarised.

K0SK0S correlations have been studied in a sample of 717 511 hadronic events collected by the DELPHI detector at LEP during 1992. An enhancement is found in the production of pairs of K0S of similar momenta, as compared with a Monte Carlo simulated reference sample. The measured values for the strength of the correlation and the radius of the emitting source of kaons are λ = 1.13 ± 0.54 (stat) ± 0.23 (syst) and r = 0.90 ± 0.19 (stat) ± 0.10 (syst) fm. This enhancement is consistent with the hypothesis that K0SK0S pairs display an enhancement, regardless of whether they come from a K0K̄0 or from a K0K0 (K̄0K̄0) system.

Two drift tubes (DTs) chambers of the CMS muon barrel system were exposed to a 40 MHz bunched muon beam at the CERN SPS, and for the first time the whole CMS Level-1 DTs-based trigger system chain was tested. Data at different energies and inclination angles of the incident muon beam were collected, as well as data with and without an iron absorber placed between the two chambers, to simulate the electromagnetic shower development in CMS. Special data-taking runs were dedicated to test for the first time the Track Finder system, which reconstructs track trigger candidates by performing a proper matching of the muon segments delivered by the two chambers. The present paper describes the results of these measurements.

In order to cope with the harsh environment expected from the high luminosity LHC, the CMS forward muon system requires an upgrade. The two main challenges expected in this environment are an increase in the trigger rate and increased background radiation leading to a potential degradation of the particle ID performance. Additionally, upgrades to other subdetectors of CMS allow for extended coverage for particle tracking, and adding muon system coverage to this region will further enhance the performance of CMS. Following an extensive R&D program, CMS has identified triple-foil gas electron multiplier (GEM) detectors as a solution for the first muon station in the region 1.6<|η|<2.2, while continuing R&D is ongoing for additional regions.

DELPHI results are presented on the inclusive production of two (KKπ)0 states in the mass region 1.2–1.6 GeV/c2 in hadronic Z decays at LEP I. The measured masses (widths) are 1274±6 MeV/c2 (29±12 MeV/c2) and 1426±6 MeV/c2 (51±14 MeV/c2), respectively. A partial-wave analysis of the (KKπ)0 system shows that the first peak is consistent with the IG(JPC)=0+(1++)/(0−+)a0(980)π and the second with the IG(JPC)=0+(1++)K∗(892)K+c.c. assignments. The total hadronic production rates per hadronic Z decay are (0.165±0.051) and (0.056±0.012), respectively. These measurements are consistent with the two states being the f1(1285) and f1(1420) mesons.

The drift tubes based CMS barrel muon trigger, which uses self-triggering arrays of drift tubes, is able to perform the identification of the muon parent bunch crossing using a rather sophisticated algorithm. The identification is unique only if the trigger chain is correctly synchronized. Some beam test time was devoted to take data useful to investigate the synchronization of the trigger electronics with the machine clock. Possible alternatives were verified and the dependence on muon track properties was studied.

Gas Electron Multiplier (GEM) technology is being considered for the forward muon upgrade of the CMS experiment in Phase 2 of the CERN LHC. Its first implementation is planned for the GE1/1 system in the 1.5 <| η |< 2.2 region of the muon endcap mainly to control muon level-1 trigger rates after the second long LHC shutdown. A GE1/1 triple-GEM detector is read out by 3,072 radial strips with 455 µrad pitch arranged in eight η-sectors. We assembled a full-size GE1/1 prototype of 1m length at Florida Tech and tested it in 20–120 GeV hadron beams at Fermilab using Ar/CO2 70∶30 and the RD51 scalable readout system. Four small GEM detectors with 2-D readout and an average measured azimuthal resolution of 36 µrad provided precise reference tracks. Construction of this largest GEM detector built to-date is described. Strip cluster parameters, detection efficiency, and spatial resolution are studied with position and high voltage scans. The plateau detection efficiency is [97.1 ± 0.2 (stat)]%. The azimuthal resolution is found to be [123.5 ± 1.6 (stat)] µrad when operating in the center of the efficiency plateau and using full pulse height information. The resolution can be slightly improved by ∼ 10 µrad when correcting for the bias due to discrete readout strips. The CMS upgrade design calls for readout electronics with binary hit output. When strip clusters are formed correspondingly without charge-weighting and with fixed hit thresholds, a position resolution of [136.8 ± 2.5 stat] µrad is measured, consistent with the expected resolution of strip-pitch/equation µrad. Other η-sectors of the detector show similar response and performance.

A novel approach which uses Fiber Bragg Grating (FBG) sensors has been utilized to assess and monitor the flatness of Gaseous Electron Multipliers (GEM) foils. The setup layout and preliminary results are presented.

The Compact Muon Solenoid (CMS) detector is one of the two general-purpose detectors at the CERN LHC. LHC will provide exceptional high instantaneous and integrated luminosity after second long shutdown. The forward region |η| ≥ 1:5 of CMS detector will face extremely high particle rates in tens of kHz/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> and hence it will affect the momentum resolution, efficiency and longevity of the muon detectors. Here, η is pseudorapidity defined as η = −ln(tan(θ/2)), where θ is the polar angle measured from z-axis. To overcome these issues the CMSGEM collaboration has proposed to install new large size rate capable Triple Gas Electron Multiplier (GEM) detectors in the forward region of CMS muon system. The first set of Triple GEM detectors will be installed in the GE1/1 region (1:6 < |η| < 2.2) of the muon endcap during the long shutdown 2 (LS2) of the LHC. Towards this goal, full size CMS Triple GEM detectors have been fabricated and tested at the CERN SPS, H2 and H4 test beam facility. The GEM detectors were operated with two gas mixtures: Ar/CO <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> (70/30) and Ar/CO <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> /CF <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</inf> (45/15/40). In 2014, good quality data was collected during test beam campaigns. In this paper, the performance of the detectors is summarized based on their tracking efficiency and time resolution.

The cross-section for the process e+e−→W+W− has been measured with the data sample collected by DELPHI at an average centre-of-mass energy of 182.65 GeV and corresponding to an integrated luminosity of 53 pb−1. Based on the 770 events selected as WW candidates, the cross-section for the doubly resonant process σ(e+e−→W+W−)=15.86±0.69(stat)±0.26(syst)pb has been measured and found to be in good agreement with the Standard Model expectation. The branching fractions of the W decay were also measured. From these a value of the CKM mixing matrix element |Vcs|=0.985±0.073(stat)±0.025(syst) was derived. Our previously published WW cross-section measurements and the derived measurement of mW have been revised and updated with the present cross-section measurement to yield mW=80.49±0.43(stat)±0.09(syst)±0.03(LEP)GeV/c2.

Background: Stereotactic body radiation therapy (SBRT) can deliver a very high dose to the tumor while minimizing the damage to the surrounding structures.The purpose of our study was to investigate local control (LC), local progression-free survival (LPFS), and overall survival (OS) to determine the impact of SBRT lung treatment in metastatic lesions.A secondary end point estimated the impact of colorectal metastases stratified for the same parameters.Methods: A total of 265 patients with, in total, 483 lesions were analyzed: 34% of patients had a diagnosis of primary non-small cell lung cancer (NSCLC) compared with 66% with lung metastases.Considering only the metastatic lung tumors, 37% of the patients presented localized colorectal metastases.Follow-up was generally undertaken at 4 weeks, and 2, 4, 6, 12 months following SBRT, and annually thereafter.Toxicities were scored according to the Common Terminology Criteria for Adverse Events definitions.Results: In our sample, LC rates at 1, 3, and 5 years were, respectively, 80%, 58%, and 44%, (median LC was 44 months), LPFS was 65%, 41%, and 36% (median LPFS was 36 months), and OS was respectively 85%, 69%, and 56% (median OS was 64 months).All patients finished their SBRT course without interruptions related to acute toxicity.No acute or late Grade 3 or higher pulmonary fibrosis was founded.Acute and late Grade 2 toxicities were 2.5%.Histology shows statistical differences in LC (P<0.01).SBRT stratified by primary tumor, excluding lung lesions from primary colorectal tumor cases, shows increased LC rates at 1, 3, and 5 years, respectively 83%, 72% and 70%.Median LC was 56 months (P<0.01).Conclusions: SBRT in lung lesions showed efficacy in both responses and maintenance.No significant toxicity was found, while good patient compliance was observed.No variables except histology showed significant differences.We observed that for patients with primary tumor metastases from the gastrointestinal region, who have undergone previous pulmonary chemotherapy treatments (2 years), there are lower response rates than the rest of the examined sample.The study suggests that SBRT treatment of lung lesions may achieve a better result if performed earlier than in other therapeutic approaches.

We report gold electroplating on ultra-compliant substrates comprising helical slow wave structures (SWSs) for traveling wave tube amplifiers (TWTAs) [1]. The novel ultra-compliant substrates are composed of edge-tethered tri-layer metal ribbons with a helical geometry of microscale diameter. After electroplating with gold, we obtain overall thicknesses of a few um. We discuss different controllable electroplating conditions that influence thickness, uniformity, roughness, and related properties of deposited gold films on helical ribbons. In addition to increasing conductance of the electroplated helical ribbons, electroplating stabilizes the helix at its equilibrium diameter, with the pitch predicted by Prakash et al .[1]. Our method of fabrication of ultra-compliant helical ribbons starts with defining strips of width 5 µm to 10 µm by optical lithography, metal evaporation, and lift-off, deposited on Si substrates coated with a sacrificial layer of Ge or GeOx,. We use Cr/Au/Cr tri-layers to create an inherent stress gradient that causes the strip to self-assemble into a helix, after etching with XeF 2 for selective removal of a sacrificial layer. Diameter and pitch of the released helices are controlled by varying the thickness, the elastic modulus, the residual stress, and the in-plane geometry of the deposited tri-layer metal strips. The gold electroplating process uses a sulphate-based gold solution in a two-electrode electrochemical setup with the helix as the cathode and a platinized mesh as the anode [2]. We deposit gold to a thickness of a few um, using a pulsed current source with variable parameters. Direct current can also be used with smaller deposition times. Our results demonstrate the application of electroplating to unconventional ultra-compliant helix of nanoscale dimensions. Reference [1] Divya J. Prakash,., Matthew M. Dwyer, Marcos Martinez Argudo, Mengistie L. Debasu, Hassan Dibaji, Max G. Lagally, Daniel W. van der Weide, and Francesca Cavallo. 2020. “Self-Winding Helices as Slow-Wave Structures for Sub-Millimeter Traveling-Wave Tubes.” ACS Nano, 2021, 15, 1229-1239. doi:10.1021/acsnano.0c08296. [2] Max G. Lagally, Anjali Chaudhary, Daniel van der Weide, Divya J. Prakash, and Francesca Cavallo, Improved Self-assembly of Helices via Electrodeposition on Freestanding Nanoribbons for TWT Application, provisional US patent application (P220249US01) Work supported by U.S. AFOSR-Award No FA9550-22-1-0086.

Based on a sample equivalent to 365 000 hadronic Z0 decays, the search in DELPHI data for pairs of leptons accompanied by a pair of charged particles is described. A total of 11 events were found in the electron channel, 9 in the muon channel and 7 in the tau channel. Results on lepton pairs with a radiated photon are also presented. The data from all channels are compatible with the expectations from standard processes. However, one event was found in the tau channel with an unusually high mass of the charged particle pair.

A measurement of the mass difference,Δm d , between the two physical B 0 states has been obtained from the analysis of the impact parameter distribution of a lepton emitted at large transverse momentum (p t ) relative to the jet axis and from the analysis of the flight distance distribution of secondary vertices tagged by either a highp t lepton or an identified kaon. In the opposite hemisphere of the event, the charge of the initial quark has been evaluated using a highp t lepton, a charged kaon or the mean jet charge. With 1.7 million hadronic Z0 decays recorded by DELPHI between 1991 and 1993,Δm d is found to be: $$\Delta m_d = 0.531_{ - 0.046}^{ + 0.050} (stat.) \pm 0.078 (syst.) ps^{ - 1} .$$ .

We present a novel application of Fiber Bragg Grating (FBG) sensors in the construction and characterisation of Micro Pattern Gaseous Detector (MPGD), with particular attention to the realisation of the largest triple (Gas electron Multiplier) GEM chambers so far operated, the GE1/1 chambers of the CMS experiment at LHC. The GE1/1 CMS project consists of 144 GEM chambers of about 0.5 m 2 active area each, employing three GEM foils per chamber, to be installed in the forward region of the CMS endcap during the long shutdown of LHC in 2108-2019. The large active area of each GE1/1 chamber consists of GEM foils that are mechanically stretched in order to secure their flatness and the consequent uniform performance of the GE1/1 chamber across its whole active surface. So far FBGs have been used in high energy physics mainly as high precision positioning and re-positioning sensors and as low cost, easy to mount, low space consuming temperature sensors. FBGs are also commonly used for very precise strain measurements in material studies. In this work we present a novel use of FBGs as flatness and mechanical tensioning sensors applied to the wide GEM foils of the GE1/1 chambers. A network of FBG sensors have been used to determine the optimal mechanical tension applied and to characterise the mechanical tension that should be applied to the foils. We discuss the results of the test done on a full-sized GE1/1 final prototype, the studies done to fully characterise the GEM material, how this information was used to define a standard assembly procedure and possible future developments.

Gas Electron Multiplier (GEM) technology is being considered for the forward muon upgrade of the CMS experiment in Phase 2 of the CERN LHC. Its first implementation is planned for the GE1/1 system in the $1.5 < \mid\eta\mid < 2.2$ region of the muon endcap mainly to control muon level-1 trigger rates after the second long LHC shutdown. A GE1/1 triple-GEM detector is read out by 3,072 radial strips with 455 $\mu$rad pitch arranged in eight $\eta$-sectors. We assembled a full-size GE1/1 prototype of 1m length at Florida Tech and tested it in 20-120 GeV hadron beams at Fermilab using Ar/CO$_{2}$ 70:30 and the RD51 scalable readout system. Four small GEM detectors with 2-D readout and an average measured azimuthal resolution of 36 $\mu$rad provided precise reference tracks. Construction of this largest GEM detector built to-date is described. Strip cluster parameters, detection efficiency, and spatial resolution are studied with position and high voltage scans. The plateau detection efficiency is [97.1 $\pm$ 0.2 (stat)]\%. The azimuthal resolution is found to be [123.5 $\pm$ 1.6 (stat)] $\mu$rad when operating in the center of the efficiency plateau and using full pulse height information. The resolution can be slightly improved by $\sim$ 10 $\mu$rad when correcting for the bias due to discrete readout strips. The CMS upgrade design calls for readout electronics with binary hit output. When strip clusters are formed correspondingly without charge-weighting and with fixed hit thresholds, a position resolution of [136.8 $\pm$ 2.5 stat] $\mu$rad is measured, consistent with the expected resolution of strip-pitch/$\sqrt{12}$ = 131.3 $\mu$rad. Other $\eta$-sectors of the detector show similar response and performance.

The CMS muon barrel drift tubes system has been recently fully installed and commissioned in the experiment. The performance and the current status of the detector are briefly presented and discussed.

The CMS Collaboration plans to equip the very forward muon system with triple-GEM detectors that can withstand the environment of the High-Luminosity LHC. This project is at the final stages of R&amp;D and moving to production. An unprecedented large area of several 100 m 2 are to be instrumented with GEM detectors which will be produced in six different sites around the world. A common construction and quality control procedure is required to ensure the performance of each detector. The quality control steps will include optical inspection, cleaning and baking of all materials and parts used to build the detector, leakage current tests of the GEM foils, high voltage tests, gas leak tests of the chambers and monitoring pressure drop vs. time, gain calibration to know the optimal operation region of the detector, gain uniformity tests, and studying the efficiency, noise and tracking performance of the detectors in a cosmic stand using scintillators.

During the High Luminosity LHC, the Drift Tube chambers installed in the CMS detector need to operate with an integrated dose ten times higher than expected at the LHC due to the increase in integrated luminosity from 300 fb-1 to 3000 fb-1. Irradiations have been performed to assess the performance of the detector under such conditions and to characterize the radiation aging of the detector. The presented analysis focuses on the behaviour of the high voltage currents and the dose measurements needed to extrapolate the results to High Luminosity conditions, using data from the photon irradiation campaign at GIF++ in 2016 as well as the efficiency analysis from the irradiation campaign started in 2017. Although the single-wire loss of high voltage gain observed of 70% is very high, the muon reconstruction efficiency is expected to decrease less than 20% during the full duration of High Luminosity LHC in the areas under highest irradiation.

The interference between initial and final state radiation in the processe + e −→μ + μ − at √s≈MZ has been studied by measuring the forward-backward asymmetry as a function of the acoplanarity angle between the final state muons. The interference is expected to be sensitive to the space-time separation of the initial and final state radiation. The measured asymmetry distribution has been compared to theoretical predictions using thekoralz generator, with and without $${\mathcal{O}}(\alpha )$$ interference. The magnitude of the interference between initial and final state radiation was found to be of the order predicted and to follow the expected distribution. Using the theoretical predictions, a value of $$\Gamma _{\rm Z} = 2.50 \pm 0.21 (stat.) \pm 0.06 (syst.) GeV.$$ has been extracted. The interpretation of this result is discussed. There is an additional uncertainty in the estimate ofΓ Z from as yet uncalculated higher order interference terms. By assuming a value ofΓ Z consistent with the world average, the data were used to estimate the size of these uncalculated corrections.

Building and operating the CMS Detector is a complicated endeavour!Now, more than 20 years after the detector was conceived, the CMS Bologna group proposes to follow the steps of this challenging project by playing "The Higgs Boson Goose Game", illustrating CMS activities and goals.The concept of the game is inspired by the traditional "Game of the Goose".The underlying idea is that the progress of building and operating a detector at the LHC is similar to the progress of the pawns on the game board: it is fast at times, bringing rewards and satisfaction, while sometimes unexpected problems cause delays or even a step back requiring CMS scientists to use all of their skill and creativity to devise new solutions.

For the High-Luminosity LHC (HL-LHC) phase the CMS GEM Collaboration is planning to install new large-size (990×220–455mm2) triple-GEM detectors, equipped with a new readout system, in the forward region of the muon system (1.5< |η| <2.2) of the CMS detector. Combining triggering and tracking functionalities the new triple-foil Gas Electron Multiplier (GEM) chambers will improve both the performance of the CMS muon trigger and the muon reconstruction/identification in CMS experiment. The addition of triple-GEM chambers to the forward region of the CMS muon system will add a necessary layer of redundancy. Starting from 2009 the CMS GEM Collaboration has built several small and full-size prototypes with different geometries, keeping improving the assembly techniques. All these prototypes have been tested in laboratories as well as with beam tests at the CERN Super Proton Synchrotron (SPS) and at Fermi National Accelerator Laboratory. In this contribution we will report on the status of the CMS upgrade project with triple-GEM chambers and its impact on the CMS performance as well as the hardware architectures and expected capability of the CMS GEM readout system.

We present a novel application of Fiber Bragg Grating (FBG) sensors in the construction and characterisation of Micro Pattern Gaseous Detector (MPGD), with particular attention to the realisation of the largest triple (Gas electron Multiplier) GEM chambers so far operated, the GE1/1 chambers of the CMS experiment at LHC. The GE1/1 CMS project consists of 144 GEM chambers of about 0.5 m2 active area each, employing three GEM foils per chamber, to be installed in the forward region of the CMS endcap during the long shutdown of LHC in 2108-2019. The large active area of each GE1/1 chamber consists of GEM foils that are mechanically stretched in order to secure their flatness and the consequent uniform performance of the GE1/1 chamber across its whole active surface. So far FBGs have been used in high energy physics mainly as high precision positioning and re-positioning sensors and as low cost, easy to mount, low space consuming temperature sensors. FBGs are also commonly used for very precise strain measurements in material studies. In this work we present a novel use of FBGs as flatness and mechanical tensioning sensors applied to the wide GEM foils of the GE1/1 chambers. A network of FBG sensors have been used to determine the optimal mechanical tension applied and to characterise the mechanical tension that should be applied to the foils. We discuss the results of the test done on a full-sized GE1/1 final prototype, the studies done to fully characterise the GEM material, how this information was used to define a standard assembly procedure and possible future developments.

For the LHC High Luminosity phase (HL-LHC) the CMS GEM Collaboration is planning to install new large size triple-GEM detectors in the forward region of the muon system (1.5<|η|<2.2) of the CMS detector.The muon reconstruction with triple-GEM chambers information included have been successfully integrated in the official CMS software, allowing physics studies to be carried out.The new sub-detector will be able to cope the extreme particle rates expected in this region along with a high spatial resolution.The resulting benefit in terms of triggering and tracking capabilities has been studied: the expected improvement in the performance of the muon identification and track reconstruction as well as the expected improvement coming from the lowering of the muon p T trigger tresholds will be presented.The contribution will review the status of the CMS upgrade project with the usage of GEM detector, discussing the trigger, the muon reconstruction performance and the impact on the physics analyses.

The hadronic photon structure functionF 2 γ has been measured in theQ 2 range from 4 to 30 GeV2/c 4 and down tox values of order 0.001, using data taken with the DELPHI detector at LEP between 1991 and 1993. A comparison is made with severalF 2 γ parameterizations with special emphasis on their lowx behaviour. A result on theQ 2 evolution ofF 2 γ is presented.

Searches for {\mbox{$ {\mathrm H} {\mathrm Z} $}} production d with the Higgs boson decaying into an invisible final state have been performedd the data collected by the DELPHI experimentd up to the centre-of-mass energy of 188.6~{\mbox{$ {\mathrm{GeV}}$}}. d The hadronic and muon pair final states of the d {\mbox{$ {\mathrm Z} $}} d boson were analysed. No signal was found. d Upper limits on the cross-section and the corresponding Higgs boson mass d limits were set d at 95\% confidence level. Combining these results with DELPHI results for the vd a 95\% confidence level Higgs mass lower limit of 92.3~{\mbox{$d {\mathrm{GeV}}$}} was obtained, independentd of the branching ratio into visible and invisible decays.

The Istituto Nazionale di Fisica Nucleare (INFN) is an Italian public research organization devoted to the study of the fundamental constituents of matter and of their interactions. Its theoretical and experimental research activities are in the fields of sub-nuclear, nuclear and astroparticle physics. INFN employs 2500 staff (scientists, technicians and administrative staff) and about 4000 associate people. In the last 20 years, the gender parity has been monitored and affirmative actions have been proposed. Statistics and actions will be presented.

Self-assembled metal helices have recently emerged as viable slow-wave structures for millimeter-through-THz traveling-wave tube amplifiers. Here we present results on the fabrication and testing of devices for DC conductivity and S-parameters measurements in the W band.

We show two routes to fabricate self-assembled helical ribbons with microscale diameter and pitch. These helices may serve as slow-wave structures in millimeter-through-THz vacuum electronic devices. The focus is on releasing metal strips by H <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> O <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> etching and XeF <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> etching of a Ge sacrificial layer. We show how the two etching methods affect the geometry of the fabricated helices and the structure of electroplated gold films on the helical ribbons.