DOCSLIB.ORG

Hadronic Recoil in the W Boson Production at LHC for a W Mass

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Hadronic Recoil in the W Boson Production at LHC for a W Mass Università di Pisa Dipartimento di Fisica "E.Fermi" Corso di Laurea Magistrale in Fisica Hadronic recoil in the W boson production at LHC for a W mass measurement with the CMS experiment CERN-THESIS-2017-157 20/09/2017 Candidato: Relatore: Olmo Cerri prof. Luigi Rolandi ANNO ACCADEMICO 2016/2017 Audentes Fortuna iuvat Alle persone che mi hanno aiutato a completare questo percorso. Che possa restare accanto a voi e ricambiare ciò che ho ricevuto. Contents Introduction 1 1 The Standard Theory of particles 3 1.1 Fields and Symmetries . .3 1.2 Spontaneous symmetry breaking and Brout – Englert – Higgs mechanism7 1.2.1 Gauge boson masses . .7 1.3 Precision test of the ElectroWeak sector . .8 1.3.1 Higher order prediction of W mass . .9 1.3.2 The global electroweak fit . 10 2 The Compact Muon Solenoid experiment 13 2.1 The Large Hadron Collider . 13 2.1.1 Proton-Proton collision physics . 16 2.2 The CMS detector . 18 2.2.1 The layers structure . 20 2.2.2 Trigger . 22 2.3 Physics object reconstruction . 22 2.3.1 Particle Flow algorithm . 23 2.4 Simulation . 24 3 The W boson mass measurement 27 3.1 From discovery to LEP . 28 3.2 W mass measurement in modern hadron collider . 31 3.2.1 Analysis strategy . 31 3.2.2 Main uncertainties . 34 3.2.3 Recent efforts summary . 36 III 4 The hadronic recoil in the W mass measurement 39 4.1 Production Mechanism . 40 4.1.1 Comparison between Z and W .................. 41 4.2 Definition ad characterization of hadronic recoil . 42 4.2.1 Detector effects in measuring the recoil . 43 4.3 Samples definition . 44 4.3.1 Events selection . 45 4.4 Hadronic recoil effect on transverse mass . 48 4.4.1 W mass sensitivity and boson transverse momentum dependence 50 4.5 A precise measurement of the recoil . 52 4.5.1 The recoils as a 2D object . 52 4.5.2 Resolution effects . 55 5 A new recoil definition 59 5.1 Recoil definitions . 60 5.1.1 An improved recoil . 61 5.2 A multivariate semi-parametric regression . 62 5.2.0.1 Neural Networks: a generic function . 62 5.2.0.2 Semi-parametric regression . 64 5.2.1 Application to recoil definition . 65 5.2.2 Details of the trained regression . 68 5.3 Goodness of the definition . 71 5.3.1 Regression - network convergence check . 72 5.3.1.1 Sum of pdfs closure . 73 5.3.2 Goodness event-by-event of recoil estimators . 76 6 Systematic uncertainties 79 6.1 Systematic effects and factorization scheme . 80 6.2 W mass fitting procedure . 81 6.3 Effect of boson kinematic mismodeling . 83 6.3.1 Estimating the systematic uncertainty . 84 6.3.2 Recoil definitions ranking . 88 6.4 Systematic on the recoil mismodeling . 90 6.4.1 Differences between data and simulations . 91 6.5 A multi-dimensional morphing procedure . 92 6.5.1 Procedure for a n-dimensional k-conditional morphing . 94 6.6 Recoil modeling effect and calibration . 96 6.6.1 Procedure check . 98 6.6.2 Systematic assessment before calibration . 99 6.6.3 Systematic assessment after calibration . 100 6.7 Porting the calibration from Z to W . 102 6.7.1 Generated instead of reconstructed boson kinematic variables . 102 6.7.2 Intrinsic MC differences between Z and W . 103 7 Conclusions 105 7.1 Future developments . 107 A DNN training details 111 Bibliography 113 Acknowledgments 127 Introduction After the discovery of the Higgs boson in 2012, the standard model of particle physics (SM) has been further validated and all its free parameters established. Using the full set of SM parameters, it is thus possible to predict with increasing precision rela- tions among observables which can be verified in experiments. The agreement between measurements and theoretical predictions is a severe consistency test for the model: possible deviations of measured values from those predictions would be a clear sign of new physics beyond the standard model. Specifically, precise determination of the W boson mass is of great importance in this testing procedure. From the time of its discovery in 1983, the W boson has been stud- ied and its mass determined in both hadron and lepton colliders. At the state of the art, the W boson mass has a smaller uncertainty in the SM pre- diction of 80:360 0:007 GeV than in the measured value of 80:385 0:015 GeV. A ± ± measurement of the W mass with an uncertainty smaller than 7 MeV might be a break- through and may result in a direct evidence of SM inconsistency. For this reason, such measurement is currently studied at the LHC. The CMS experiment is planning to de- liver a measurement of W mass within the next years. At hadron colliders, production of on-shell W bosons is tagged by the high transverse momentum (pT ) charged lepton from its decay in the leptonic final state, the only one suitable for a precise mass mea- surement. In practice, W mass is extracted from data via a fit to several distributions, which need to be understood and optimized up to an unprecedented level of precision. In the first chapter of this work, an overall picture of the theoretical basis is pre- sented. Starting from the foundations of the Standard Model, Higgs mechanism and electroweak symmetry breaking are introduced, focusing on their role of providing SM gauge boson with masses. The important facts of electroweak precision test are also introduced in the last part of the first chapter. After an overview of the Large Hadron Collider (LHC), which is currently operating at CERN, the second part of this work describes the Compact Muon Solenoid (CMS) experiment, aimed to explore in depth particle physics up to the TeV scale: the main 1 features of the subdetectors are briefly described, together with the reconstruction al- gorithms; focus has been put mostly on those features of interest for W mass physics. The third chapter is devoted to discuss the past and the on going efforts for the W boson mass measurement. The original work developed during the thesis is fully discussed in chapters four, five and six. Two are the main objectives: to deepen the knowledge of the variables used in the W mass measurement, with particular attention on the event-by-event experimental estimator of the boson transverse momentum; to define and calibrate an experimental definition of the recoiling system to the W , suitable for the real measurement process at the CMS experiment. Transverse momentum of the recoil and of the boson are two faces of the same coin: both are crucial in the extraction of the mass value. Events in which the W boson decays into a muon and a neutrino are considered. The W mass is extracted from the distributions of the modulus of the lepton trans- verse momentum (pµ) and of the transverse mass (MT ), a scalar quantity function of the lepton momentum and the recoil, which is the vectorial sum of the momenta of all reconstructed particles excluding the lepton. With the purpose to maximize the performance in terms of systematic uncertainty on the final measurement, a new ex- perimental definition of the recoil, based on machine learning algorithms, is discussed. As support to the remarkable impact of my work, there are reported cross checks and performances of the new definition, in terms of resolution and uncertainty improvement for a W mass measurement. In the last chapter, recoil-related systematic uncertainties on the W mass measurement are presented. Furthermore, it is reported a new method, based on multi-dimensional morphing, used to calibrated the Monte Carlo simulation using collision data. The systematic uncertainties of the W mass measurement before and after this calibration are studied. Finally, conclusions summarize the main results, underlining the importance of the work, and suggesting possible future developments. Document notation Throughout this document the classical notation of high energy physics will be used. In particular, the value of the speed of light and the Plank constant are set to c = 1 and ~ = 1, so that masses, energies and momenta are all expressed in electron volts (eV). All the angles are represented in the space [ π; π]. − Tesi Magistrale - Olmo Cerri 2 Chapter 1 The Standard Theory of particles The “Standard Model” (SM) is the theory that summarizes the knowledge we have about fundamental components of matter and their interactions; it describes a wide range of phenomena and has been tested experimentally with a remarkable accuracy, even if there are some important problems to which it gives no satisfactory answer. The theory has emerged gradually in almost a century of theoretical and experimental investigations and it is now fully established. I will describe it from the logical point of view. Quantum field theory, the framework in which SM is formulated, is a vast subject and even a short but comprehensive resume of it would be too long for this thesis, so I will only introduce the key concepts useful later on. This compilation chapter is thus devoted to describe the SM accurately enough to serve as a theoretical background to the main subject of this thesis. A complete reference can be found in the original papers, such as [1], and in the classic textbooks, such as [2]. Additionally, given the main focus of this thesis, all mathematical details are left over. 1.1 Fields and Symmetries The standard model is based on the existence of 17 different elementary fields which can be grouped into three categories.
Load more

Recommended publications
  • Experimental Measurement of Rifle Dynamics During the Range Shooting of Biathlon Weapons
    Available online at www.sciencedirect.com ScienceDirect Procedia Engineering 112 ( 2015 ) 349 – 354 7th Asia-Pacific Congress on Sports Technology, APCST 2015 Experimental measurement of rifle dynamics during the range shooting of biathlon weapons Andrey Koptyug*, Mats Ainegren SportsTech Research Center, Mid Sweden University, Akademigatan 1, SE-831 25, Östersund, Sweden Abstract Some of the shooting training that biathletes implements takes place indoors, even in hotel rooms or at home, through so-called "dry firing" training. It involves imitating shooting at a target with real rifle but without ammunition, when the result is evaluated by various electronic devices counting the number of virtual hits. But dry firing cannot adequately represent real shooting, as it does not produce any rifle recoil, which significantly limits its value for the training. To reach a higher realism of the dry firing training a system mimicking the weapon recoil is therefore needed. Present research aims to overcome an existing lack of data on the dynamics of small caliber rifles recoil dynamics. Present paper describes first measurement results acquired in the controlled environment of the shooting range. Two types of experiments were carried out with firing freely suspended rifle and when backed with the force measurement device (load cell). Average recoil peak force values were reaching 5 kg, rising from zero for about 10-15 ms and keeping altogether for about 30-40 ms. Corresponding energy going into the recoil motion of the rifle is found to be about 390 J. The measured values provide an adequate input for designing the devices mimicking the biathlon weapon recoil in dry firing training.
    [Show full text]
  • Engineering Design Handbook Guns Series Muzzle Devices.Pdf
    UNCLASSIFIED AD NUMBER AD838748 LIMITATION CHANGES TO: Approved for public release; distribution is unlimited. FROM: Distribution authorized to U.S. Gov't. agencies and their contractors; Administrative/Operational Use; MAY 1968. Other requests shall be referred to Army Materiel Command, Alexandria, VA. AUTHORITY USAMC ltr 22 Jul 1971 THIS PAGE IS UNCLASSIFIED AM Lp - AMC PAMPHLET ENGINEERING DESIGN HANDBOOK GUNS SERIES MUZZLE DEVICES 3 0 SF' lC£8 ' m® -WY SUM * ©?V BOT DKTHTIJ HEADQUARTERS, U.S. ARMY MATERIEL COMMAND MAY 1968 REDSTONE SCIENTIFIC INFORMATION CENTER nun 5 0510 00231346 5 FTEADQUARTERS UNITED STATES ARMY MATERIEL COMMAND WASHINGTON, D.C. 20315 AMC PAMPHLET 17 May 1968 No. 706-251 ENGINEERING DESIGN HANDBOOK GUNS SERIES MUZZLE DEVICES This pamphlet is published for the information and guidance of all concerned. (AMCRD-R) FOR THE COMMANDER: OFFICIAL : CLARENCE J. LANG Major General, USA Chief of Staff Chief. Administrative Office DISTRIBUTION Special AMCP 706-251 PREFACE The Engineering Design Handbook Series of the Army Materiel Command is a coordinated series of handbooks containing basic in- formation and fundamental data useful in the design and develop- ment of Army materiel and systems. The handbooks are authorita- tive reference books of practical information and quantitative facts helpful in the design and development of Army materiel so that it will meet the tactical and the technical needs of the Armed Forces. This handbook is one cf a series on Guns and presents informa- tion on the fundamental operating principles and design of muzzle devices. Because of higher priorities assigned in the past to other activities, progress in the design of bore evacuators, noise suppres- sors, and smoke suppressors was not shared with that of muzzle brakes, blast deflectors, and flash suppressors.
    [Show full text]
  • 1) a Moving Electron of Mass Me and Initial Speed V1 Collides Head on with an Initially Stationary Hydrogen Atom of Mass Mp
    1) A moving electron of mass me and initial speed v1 collides head on with an initially stationary Hydrogen atom of mass mp. The collision is elastic and remains 1-dimensional. If mp / me = 1840: (a) What is the center of mass velocity? (b) What does this collision look like from the center of mass reference frame? Draw two pictures (before and after ). (c) what fraction of the electron’s initial kinetic energy is transferred to the Hydrogen atom ? 2) A certain spring is found not to conform to Hooke’s law. The return force it exerts on being 3 extended a distance x is found to be F = -(k1x + k2x ). a) Compute the potential energy function for this force. b) If a mass m is attached to the spring and stretched out to a distance xo, what speed will it have on release when it is at the position x = xo/2 ? 3) A stone of weight w is thrown vertically upward into the air from ground level with initial speed v0. If air drag exerts a force of constant magnitude f on the stone throughout its flight: a) what is the maximum height reached by the stone ? b) what is the return speed just before impact on the way down ? 4) A 1400 kg cannon fires a 70 kg shell with a muzzle speed of 556m/s.If the cannon is mounted on frictionless rails and set at an elevation of 39 degrees above the horizontal: a) What is the recoil speed of the cannon? b) At what angle with respect to the ground is the shell projected? 5) Newton's second law is best stated in terms of momentum because in that form variable mass problems can be simply treated.
    [Show full text]
  • Simulation of Cannon Recoil Dynamics for Light Vehicles Using Single Body Models
    UNCLASSIFIED/UNLIMITED Simulation of Cannon Recoil Dynamics for Light Vehicles Using Single Body Models David C. Rutledge, Ph.D. Staff Engineer United Defense 4800 East River Road Minneapolis, MN 55421-1498 [email protected] SIMULATION OF CANNON RECOIL DYNAMICS FOR LIGHT VEHICLES USING SINGLE BODY MODELS Firing a large caliber cannon mounted on a lightweight vehicle can result in severe pitching reaction angles and driver accelerations. These dynamic responses must be small enough to allow the crew and vehicle to fight effectively, hence their prediction is a key aspect of weapon integration with land vehicles. United Defense uses two classes of models to predict cannon firing dynamics: • Single body, time invariant, models that focus more on delivering timely results. These are best used to close in on the correct answer, which is appropriate for rapid prototyping efforts and trend studies. • Multibody transient dynamic models such as Dynamic Analysis and Design System (DADS), which can deliver more accurate results. Such models are used for detailed design and development. The single body, time invariant, vehicle/suspension models developed at United Defense contain simplified representations of vehicle components, resulting in reduced modeling fidelity. The primary simulation inputs include firing impulse and peak force. The vehicle mass properties, geometry, and position of any stabilizers then determine vehicle response. The primary outputs are vehicle reaction angle and driver acceleration, which are determined by calculating the initial angular velocity, pitching and rolling moments, and lateral force from firing. The outputs are typically plotted as a function of cannon azimuth and elevation. The models are then tuned to correlate with previous results from firing data and DADS simulations, increasing their accuracy.
    [Show full text]
  • The Artillery News
    THE ARTILLERY NEWS. JUNE – AUGUST 2007 Official Correspondence. R.A.A Assoc. of Tas. Inc. Hon. Secretary, Norman B. Andrews OAM., SBStJ. Tara Room, 24 Robin St; Newstead. Tas. 7250. E-Mail: [email protected] R.A.A. Association of Tasmania Inc. Homepage: http://www.tasartillery.o-f.com/ R.A.A.A.T. NORTHERN HISTORICAL- SOCIAL WING. APRIL 2007 The second informal get-together for 2007 of the R.A.A.A.T. Historical- Social Wing group was held at the QVM&AG at 2.00 p.m. on Thursday 12th April, 2007 and was attended by:- Norman Andrews (Hon. Sec.), Gunter Breier, Terry Higgins, Graeme Petterwood, Lloyd Saunders, Marc Smith, Frank Stokes, Charles Tee and Rick Wood.. We did receive apologies from several members - and we were aware of others who are still on the sick list – so ‘Get Wells’ are extended We also extend our sincere sympathy to our member Bob Brown who recently lost his dear wife through illness. Hang in there Bob…! Norm read several notes he had received from other Associations regarding their activities and also advised us of an invitation from Reg Watson regarding the Annual Boer War Commemorative Day which is to be held on Sunday 10 June 2007 commencing 12.00 noon at the Boer War Memorial in Launceston’s City Park. There will be an opportunity to present flowers, posy or wreath in memory of those Tasmanians who fought in and perhaps died in the South African War (1899-1902) Further inquiries phone Reg Watson 0409 975 587. 1 Launceston contact also will be Mr.
    [Show full text]
  • Recoil Reduction Method of Gun with Side to Rear Jet Controlled by Piston Motion
    S S symmetry Article Recoil Reduction Method of Gun with Side to Rear Jet Controlled by Piston Motion Ming Qiu 1,*, Peng Si 1, Jie Song 1 and Zhenqiang Liao 1,2 1 School of Mechanical Engineering, Nanjing University of Science and Technology, Nanjing 210094, China; [email protected] (P.S.); [email protected] (J.S.); [email protected] (Z.L.) 2 School of Mechanical and Electrical Engineering, Global Institute of Software Technology, Suzhou 215163, China * Correspondence: [email protected] Abstract: Excessive recoil severely restricts the loading of high-power traditional guns on modern vehicles. To reduce the recoil without breaking the continuous firing mode and reducing the projectile velocity, a recoil reduction method that controls the lateral ejecting of propellant gas by a piston was proposed. The recoil reduction device is symmetric about the barrel axis. First, a one-dimensional two-phase flow model of interior ballistic during the gun firing cycle was established. Next, the MacCormack scheme was used to simulate, and the piston motion was gained. Then the propagation of the rarefaction wave in the barrel was presented. Finally, the propulsion difference between the piston-controlled gun and the traditional gun was discussed. The results showed that the recoil momentum was reduced by 31.80%, and the muzzle velocity was decreased by just 1.30% under the reasonable matching of structural parameters. Keywords: two-phase flow; recoil reduction; rarefaction wave; piston motion; fluid-solid coupling Citation: Qiu, M.; Si, P.; Song, J.; Liao, Z. Recoil Reduction Method of Gun with Side to Rear Jet Controlled 1.
    [Show full text]
  • Rifle and Shotgun Recoil Test System
    Rifle and Shotgun Recoil Test System A Senior Project presented to the Faculty of the Department of Mechanical Engineering California Polytechnic State University, San Luis Obispo In Partial Fulfillment of the Requirements for the Degree Bachelor of Science in Mechanical Engineering by Benjamin Canfield-Hershkowitz Trevor Foster William Meijer December 2013 © 2013 Benjamin Canfield-Hershkowitz, Trevor Foster, and William Meijer Statement of Disclaimer Since this project is a result of a class assignment, it has been graded and accepted as fulfillment of the course requirements. Acceptance does not imply technical accuracy or reliability. Any use of information in this report is done at the risk of the user. These risks may include catastrophic failure of the device or infringement of patent or copyright laws. California Polytechnic State University at San Luis Obispo and its staff cannot be held liable for any use or misuse of the project. ii Abstract This project for Weatherby, Inc. requires a simple device to test the recoil force of their shotguns and rifles to determine the effectiveness of recoil suppression methods. A bench mounted device that secures the gun and records firing data to a portable computer was created. This project was completed for the Senior Project requirement for a Bachelors of Science in Mechanical Engineering from California Polytechnic State University, San Luis Obispo. The completed prototype was successful in measuring the recoil force and energy for Weatherby’s rifles. The recoil energy from the prototype differed from the calculated theoretical recoil energy with a small enough percent error to be deemed accurate. The differences between these values are lower than the margin of error for all measurements.
    [Show full text]
  • Gunsmithing Price List
    Gunsmithing Price List General Labor Rates Inspect and Prepare quote Free Boresight Scope $15.00 Mount and Boresight Scope $25.00 Minimum Shop charge $40.00 Labor by Hour $80.00 General Services Complete Cleaning (DCOA disassemble, clean, oil, assemble) $60.00 Rust Removal / Excessively Dirty +$20.00 Zero Rifle at range (not including ammunition or rage fees) $60.00 Trigger Work starts at $80.00 Stock Services Inlet & Glass Bed semi inlet stock $80.hr Install Aluminum pillars and glass bed $120.00 Glass Bed Finished Stock $100.00 Install Swivel Studs $50.00 Inlet stock for new bolt handle $60.00 Fit & Install Recoil Pad (not including price of pad) $45.00 Muzzle Brakes Remove & Reinstall New Brake or Silencer $40.00 *If very hard to remove, i.e. red Loctite +$20.00 1.16.18 Wood Refinishing by Style Hand rubbed oil finish High gloss leaving grain of wood open $200.00 Hand rubbed oil finish High gloss completely filling the grain $320.00 Sprayed on oil, Satin finish open grain $140.00 Sprayed on oil, Satin finish filled grain $220.00 Sprayed on oil, High Gloss filled grain $300.00 Each of the following is an additional charge of $40.00 and will be assessed at the standard labor charge Oil soaked stocks Removal of Large dents Crack repair Stripping epoxy Staining 1.16.18 --------------------------------------------------------------------------------------------------------------------- Metal Finishing Black Oxide and Parkerizing: (Includes disassembly, abrasive blasting and reassembly) Pistols: $120.00 Rifles/Shotguns: $175.00 Removing scratches and pitting: $80/hour Bluing: (Includes disassembly, abrasive blasting and reassembly) Pistols (Matte Finish): $150.00 (Semi): $180.00 (High Polish): $200.00 Rifles/Shotguns (Matte Finish): $200.00 (Semi): $250.00 (High Polish): $300.00 *Matte Finish is minimal scratch/pitting removal and abrasive blasting before the bluing process.
    [Show full text]
  • Higgs Recoil Mass and Cross-Section Analysis at ILC and Calibration of the CALICE Siw ECAL Prototype H
    Higgs Recoil Mass and Cross-Section Analysis at ILC AND Calibration of the CALICE SiW ECAL Prototype H. Li To cite this version: H. Li. Higgs Recoil Mass and Cross-Section Analysis at ILC AND Calibration of the CALICE SiW ECAL Prototype. High Energy Physics - Experiment [hep-ex]. Université Paris Sud - Paris XI, 2009. English. tel-00430432 HAL Id: tel-00430432 https://tel.archives-ouvertes.fr/tel-00430432 Submitted on 6 Nov 2009 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. Universit´ede Paris-Sud LAL 09-118 Centre d’Orsay Octobre 2009 Higgs Recoil Mass and Cross-Section Analysis at ILC AND Calibration of the CALICE SiW ECAL Prototype par Hengne LI M. A. Djouadi Rapporteur Mme J. List M. R. P¨oschl Directeur de la th`ese M. M.A. Thomson Rapporteur M. G. Wormser Pr´esident M. D. Zerwas To my wife Xiaoying and my daughter Emma. Abstract The major topic of this dissertation is the study of the Higgs recoil mass and the cross section measurements using the Higgs-strahlung process with Z µ+µ− and → e+e−, based on the detailed ILD detector simulation.
    [Show full text]
  • 25 Pounder Quick Firing Gun Development During World War I the Main British Field Guns Were the 18 Pounder QF Gun and 4.5 Inch Howitzer
    25 Pounder Quick Firing Gun Development During World War I the main British field guns were the 18 pounder QF gun and 4.5 inch howitzer. The 18 pounder fired a fixed round at 1615 feet per second which meant the range of the gun could only be varied by changing the elevation at which the barrel was fired. Its elevation was restricted to between -50 and +160 for the Mark II or +360 for the Mark IV (range 6525 and 9300 yards respectively). The 4.5 inch ammunition was separate loading, it being possible to separate the shell and cartridge. The brass cartridge case contained five charges. Range of the howitzer could be varied by both changes in elevation and changes to the number of charges used in the cartridge. It fired a 35lb shell to a maximum range of 6600 yards (later 7300 yards) with an elevation of between -50 and +450. 18 Pounder shrapnel round The 4.5 inch cartridge case 4.5 inch round showing the showing the brass cartridge showing the five charge bag projectile seated in the brass case which is fixed to the rings. Removal of rings cartridge case. The projectile projectile. commenced from the top and is not fixed to the case would result in a lower muzzle allowing the removal of velocity and therefore charge bags from the case. decrease in range. Soon after the end of World War I the Royal Artillery Committee, in conjunction with the Director, Royal Artillery began examining various options for a new field gun with a planned range of 15,000 yards and the combined capabilities of both the gun and a howitzer.
    [Show full text]
  • Stress Analysis of Integrated 12.7 Mm Machine Gun Mount
    Scientific Technical Review, 2016,Vol.66,No.4,pp.47-51 47 UDK: 623.56.622.4.547.551.2 COSATI: 19-06, 20-11 Stress Analysis of Integrated 12.7 mm Machine Gun Mount Aleksandar Kari 1) Dušan Jovanović1) Damir Jerković1) Nebojša Hristov1) The paper describes the problem of integration 12.7 millimeters machine gun on the mobile platform. Based on the dimensions of the machine gun modeling of machine guns mount with cradle is done. The completed model is fully functional and realistic. Using optimized internal ballistic parameters the calculations of recoil forces and loading of mount and rotating bearing are executed. The loading calculation of bearing was made in two ways. In the first case finite element method is applied and software package FEMAP was used. The second method is based on calculating the resistance components of bearing from the equilibrium condition. At the end the comparative analysis of data obtained from these two methods was done. Key words: machine gun, caliber 12.7 mm, recoil force, stand, bearings, load calculations, stress analysis, finite element analysis, integrated weapon. Introduction Table 1. Tactical - technical characteristics of machine gun M87 HE resistance of weapon and its firing stability depends Characteristic Value T on the value of recoil forces [1]. In the case of the Caliber, d 12,7 x 108 mm integration of weapons, if the barrel is rigidly connected to the Barrel length, l 1100 mm mount, the recoil force is fully transmitted to the mount. In Total length of machine guns, L 1560 mm order to avoid inconveniences of such connections, or Weight of machine guns, m 24,8 kg extended firing time load mount and to reduce its intensity, Rate of fire, n 700 bullet/min.
    [Show full text]
  • Why Demand Realistic Recoil?
    WHY DEMAND REALISTIC RECOIL? it only looks this easy Until you pull the trigger... Pull the trigger on any firearm and you will immediately understand Newton’s law about equal and opposite reactions. Recoil is an inseparable part of shooting. It instantly affects how you engage the target. And the effects are amplified for machine guns. Each machine gun round changes the lay of fire. Recoil makes the barrel on a .50 caliber dance as the weapon fires. Add on the long effective range of the weapon and that barrel dance means rounds can fan wildly as they streak down range. Gunners must constantly adjust to the recoil and re-engage the target. Fact is, training with recoil is critical. Why is realistic recoil missing from so many Machine gun trainers? Most machine gun simulators don’t even have recoil. It’s simple: put sights on the target and shoot happily certain that you’ll stay on target all the time. GUN ACTIVE RECOIL But, it’s utterly unrealistic...just a simple video game. ACME’S Gun Active Recoil Unit (GAR®) is a Some machine gun simulators provide ‘notional’ patented, electro-mechanical system that recoil. These guns may buzz a bit or lightly pop-pop- replicates the recoil intensity of the actual pop using compressed gas. And gas systems just don’t provide high rates of fire or realistic recoil. weapon when firing. It’s full-force recoil at full rate of fire for machine guns. The idea is that notional recoil reinforces the cue ® when the gunner fires. But, notional recoil doesn’t The GAR system does not require blanks or really disrupt the weapon sight picture or drive pneumatic charges – it simply plugs into an ® the weapon off target when firing.
    [Show full text]