Week 6-10 Nuke Flashcards

Question

What is colourless?

Answer 1

Mixing all three colours or all 3 anti colours produces a colourless or white charge

Answer 2

Quarks combined in groups of 2 or 3 to make neutral coloured hadrons

Answer 3

Quarks, uud

Answer 4

Quarks dud

Answer 5

Integer charge

Answer 6

Electrons, muon, tauon

Answer 7

All neutrinos

Answer 8

Number used to track the conservation of leptons in particle interactions

Answer 9

The type of lepton i.e. electron flavour, muon flavour, tau flavour

Answer 10

The total number is conserved during interactions

Answer 11

Particles that are the opposite of regular matter particles with same mass and spin but opposite electric charge and lepton number

Answer 12

From energy momentum equation: E^2 = p^2c^2 + m^2C^4 - when solved end up with +/- answer due to square root - negative energy solution -> particle travelling the opposite direction in time i.e antiparticle

Answer 13

Specific type of bosons that are force carriers (not all bosons are) and transmit force between particles

Answer 14

A type of particle that carries weak force - W or Z

Answer 15

Force carrier for EM force, massless, spin -1 - Stable and is its own antiparticle

Answer 16

Fundamental number describing the strength of EM force and helps to determine how strongly charged a particle is - alpha - = 1/137

Answer 17

Intermediate - mediates force Vector - all have spin 1

Answer 18

Roughly size of nucleus

Answer 19

Quarks, as only these carry colour charge

Answer 20

The constant of the strong force which determines the strength of strong force interaction

Answer 21

10^-25 secs

Answer 22

Small enough to be ignored

Answer 23

Boson: Gluon g Range: 10^-15m Relative strength: 1 Couples to: colour

Answer 24

Boson: Photon Range: infinite Relative strength: ~1/137 Couples to: electric charge

Answer 25

Boson: W+,W-,Zo Range: 10^-18 Relative strength: ~10^-6 Couples to: ‘Weak charge’

Answer 26

Boson: Graviton Range: infinite Relative strength: ~10^-39 Couples to:mass

Answer 27

The range of force is related tot he energy that the intermediate vector boson can borrow from one particle to give to another - substitute c=x/t into Et > h/2

Answer 28

No decays are allowed such that e,n and p make up normal matter

Answer 29

10^-23 to 10_-20 secs

Answer 30

10^-20 to 10^-16sec

Answer 31

10^-13secs or longer

Answer 32

Beta decay via weak interactions

Answer 33

An extremely short-lived unstable particle whose existence and properties are inferred from peaks in energy scattering

Answer 34

Spin 0, neutral, has mass but no other quantum numbers and coupling with other particles is proportional to mass

Answer 35

Energy gained by one electron when subjected to a PD of 1 volt

Answer 36

System of units where C, G and h are set to 1

Answer 37

Calculations are simplified as c=c^2=c^4 = 1and everything in dimensions of energy

Answer 38

H bar, Fundamental unit of action

Answer 39

E = mc2 - c2 = 1

Answer 40

Mass, energy, momentum

Answer 41

Length, time

Answer 42

E^2 = p^2c^2 + M^2c^4 - c^2 and C^4 = 1 - and E=mc2 where c2 = 1

Answer 43

Debroglie where h=1 Lambda = 1/p E2 = p2c2 + m2c4

Answer 44

Heisenberg’s: Delta E delta t > h bar where h bar =1 ET = 1

Answer 45

Probability a specific process will occur

Answer 46

Measure of area - 10^-28m2

Answer 47

Gamma = 1/ (SQRT( 1-beta^2) B = v/c

Answer 48

Beta = p/E

Answer 49

Gamma = E/m

Answer 50

1. Laws of physics valid in all inertial frames 2. Speed of light constant and same in all frames

Answer 51

x’ = gamma (x-vt) OR x = gamma (x’+vt’)

Answer 52

Moving frame

Answer 53

T’ = Gamma (t-(Vx/c^2) ) OR T = Gamma (t’+ (Vx’/c^2) )

Answer 54

an object at rest in one frame appears shorter from moving frame

Answer 55

Length in moving frame

Answer 56

Lo = x’2 - x’1 = gamma (x2-x1) = gamma L

Answer 57

Process in rest frame appears loner from moving frame

Answer 58

Delta t = t2 - t1 = Gamma (t’2 - t’1) = Gamma Delta t’

Answer 59

Cosmic ray muons - should only travel 0.6km and not reach earth but due to time dilation travel 70 more than classically expected Also accelerators - need to take into account length contraction

Answer 60

A vector with 4 components - 3 form space, 1 for time

Answer 61

Same under all Lorentz transformations

Answer 62

- Denoted with subscript - Represents how coordinates or vector components change when we change reference frames - Transform in opposite way to - Act more like “coordinates” that are aligned with new reference frame Keeps physical interpretation intact but alter how we describe the vector in the new frame

Answer 63

- Denoted with superscript - Represents how coordinates or vector behaves when we change reference frames - Transform in opposite way to covariant - Transform in way that makes the vector itself remain the same across different observers Changes components in a way that compensates for changes when you move to a new reference frame

Answer 64

Invariant ones

Answer 65

Means a four squared vector^2 >0 so the vector A is time-like Time-like = separation between 2 events are close enough that they can be connected by something moving slower than c and one could be influenced by the other. Can travel from one to the other without reaching c

Answer 66

A, a four squared vector = space like Separation is large enough that nothing,not even light, can travel from one to the other i.e. outside each other’s light cone so cannot influence each other

Answer 67

A transformation that changes the reference frame of an object moving at a constant velocity relative to another

Answer 68

The frame where the laboratory is taken to be at rest

Answer 69

The centre of mass frame is where the observer is taken to be travelling with the same speed as the centre of mass of the system

Answer 70

(τ ) is the time interval for an object at rest

Answer 71

The amount of a physical process that a system undergoes eg. the lifetime of an unstable particle, which is an intrinsic property of that particle

Answer 72

The distance between two points measured by an observer who is at rest relative to both of the points

Answer 73

The distance between two points measured by an observer who is at rest relative to both of the points.

Answer 74

of an object relative to an observer is the ratio between observer-measured displacement vector dx and proper time dτ (as measured in the frame moving with the object.

Answer 75

1st term = rest mass energy 2nd term = classical KE Subsequent terms

Answer 76

At high relative velocities

Answer 77

When v is small with respect to c

Answer 78

Rest mass energy

Answer 79

Same mass for all observers regardless of reference frame or how the system is moving

Answer 80

It can be equated before and after interactions

Answer 81

Sticky, explosive and elastic

Answer 82

Change in kinetic energy

Answer 83

Kinetic energy decreases but the total rest mass energy increases (ie. Heavier particles are made in the process)

Answer 84

Kinetic energy increases and the rest mass energy decreases (ie. Lighter particles are produced in the process such as π sup 0 → γγ)

Answer 85

Both total kinetic energy and rest mass energy are conserved (ie. The particles don’t change type.)

Answer 86

One where particles collide and change direction or energy

Answer 87

The two particles simply collide, exchange some momenta and fly away at different angles. A + B → A + B

Answer 88

New particles are produced and the products of the interaction are different. A + B → 1 + 2 + ... + N.

Answer 89

Explosive and sticky

Answer 90

Fixed target or colliding beam

Answer 91

Collisions are physical interactions from direct contact Scattering is interactions where interaction is change in direction or energy

Answer 92

One of the particles (B the target) is stationary, whilst the other (A) is delivered in a beam with high momentum

Answer 93

Both particles have momenta in opposite directions.

Answer 94

the denominator is boosted and the numerator not so from rest frame angle appears smaller

Answer 95

Device that uses EM fields to produce high energy fields

Answer 96

-Shorter than typical hadron nuclear (10^-15m)

Answer 97

From hadron radius and DeBroglie’s, 0^2 MeV

Answer 98

- Known collision position • Known initial particle type • Controlled energies • High frequency (more collisions, more interactions)

Answer 99

To define the performance of an accelerator

Answer 100

A measure of how many interactions happen

Answer 101

R = sigma L - sigma = interaction cross section, L = luminosity

Answer 102

Cumulative luminosity over time

Answer 103

Lie perpendicular to the direction of motion of the particles will constrain them to a circular trajectory perpendicular to the field.

Answer 104

They are used to counteract the electrostatic repulsion between the particles and to keep the beam focuse

Answer 105

Direct electric current machines - still used as first element in many accelerator chains - cannot alone achieve the required E¯ fields for modern particle accelerators due to voltage breakdown and discharge

Answer 106

- creates a large electric potential (up to ≈ 1 MV before discharges become a limitation) through a ladder of capacitors and diodes

Answer 107

- collects charged positive ions on a dome. This build up of positive charge can then be used to repulse injected positive ions inside the dome, accelerating up to voltages of ≈ 12 MeV - avoid the inevitable voltage breakdown issues and achieve significantly higher particle energies, the solution is to apply a limited potential multiple times at Radio Frequency

Answer 108

LINACS - consist of a linear chain of electromagnets and vacuum drift tubes. - Electromagnets, called RF-cavities, are located at the ends of the drift tubes to accelerate the particles through the chain. - electromagnets alternate (at radio frequency) sign to attract particles towards them, then as the particles pass they switch sign to repel the particles away from them - drift tubes get longer and longer along the chain to account for the increasing speed of the particles

Answer 109

- overcome the problem of building such long chains. -a synchrotron uses synchronously ramped magnetic and electric fields to accelerate charged particles, which travel round the same ring multiple times, accelerating each time. - consist of an alternating series of RF cavities, quadrupole magnets and dipole magnets.

Answer 110

A type of acceleration using synchronously ramped EM fields until emit synchrotron radiation

Answer 111

Intense bright light from charged particles when accelerated to near speed of light and forced on curved paths by fields

Answer 112

- Worl’ds most powerful accelerator (CERN) - produces proton-proton collisions at a centre of mass energy of 13 TeV

Answer 113

1. Protons are produced from bottled hydrogen gas, using an electric field to strip the electrons. • 2. The LINAC-4 then accelerates the protons up to 160 MeV. 3. The protons are then injected into the proton synchrotron (PS) and accelerated up to 25 GeV. 4. The Super proton synchrotron (SPS) with a radius of 1.1 km then accelerates the protons up to 450 GeV. 5. Finally the protons are injected into the two beam pipes of the 27 km circumference LHC, which takes 4 minutes and 20 s to fill and then 20 minutes to reach beam energies of 6.5 TeV.

Answer 114

Type of synchrotron accelerator specifically designed to accelerate protons to near c

Answer 115

Accelerated protons and heavy ions to near c. Called super due to higher energies than proton

Answer 116

Change in E is proportional to m^-4

Answer 117

Synchrotron radiation has more impact for lighter particles such as e- compared to heavier e.g. p

Answer 118

the old cyclical collider replaced by LHC due to higher energies

Answer 119

Large hadron collider?

Answer 120

Pathways in particle accelerators that use unstable particle decay of secondary particles to create a beam of the desired particles

Answer 121

High-powered magnets shaped like horns in particle physics used to focus on direct a beam of particles.

Answer 122

A device in particle accelerators that safely absorbs and disposes of unwanted or residual particle beams after completing their intended use

Answer 123

- Beams of protons from the main ring accelerator are directed onto a fixed graphite target producing, amongst other things, energetic charged pions - The pions are directed into a decay volume via magnetic horns. - The polarity of these horns will select either positive or negative pions, hence producing either neutrinos or anti-neutrinos via the decays - Muons absorbed by beam dump - Neiutrnos Cary on in a colllimated neutrino beam as so weakly interacting

Answer 124

Short for pi mesons - mediate strong force

Answer 125

with the atomic nucleus via the strong interaction

Answer 126

Charged particles via EM force

Answer 127

Ionisation energy loss or radiation energy loss

Answer 128

Cockcroft Walton Van de Graff

Answer 129

3 kHz - 300GHz

Answer 130

Linear and cyclic

Answer 131

Devices in particle accelerators that maintain an air and dust free environment so the particles can travel unobstructed

Answer 132

Hollow meta structures in accelerators resonant at specific RF to accelerate particles through the chain

Answer 133

The length of the accelerator chain

Answer 134

SLAC - Stanford linear accelerator LINAC 4 at Cern

Answer 135

When charged particles excite and ionize atoms along their path

Answer 136

EM radiation is emitted as the charged particle passes through the material.

Answer 137

Except e +-/, ionisation

Answer 138

-Describes the rate at which charged particles lose energy via ionisation as they pass though matter

Answer 139

Crucial in understanding stopping power of material for high energy particles

Answer 140

highly relativistic particles

Answer 141

1. Curve depends on the particle velocity, not mass - can identify particle just with momentum, p. 2. At low βγ (left hand side of fig 3) the particle speed is comparable to the speed of atomic electrons - large fraction of the energy loss is due to excitation of atomic and molecular levels rather than ionisation. - −dE/dx is falling rapidly due to the 1/β2factor. 3. The minimum −dE/dx is independent of the material - minimum only depends on βγ of the particle. 4. Log factor gives relativistic rise on RHS - For Betagamma>500, radiation losses in nuclear field dominate

Answer 142

- Where -dE/dx is a minimum - we say the particle is acting as a minimum ionising particle (MIP)

Answer 143

−dE/dx depends on the density, ρ, atomic number, Z, and atomic mass, A, of the target

Answer 144

Radiation energy loss

Answer 145

Extremely high energies for other charged particles

Answer 146

A positron - antimatter of electron

Answer 147

- Braking radiation in German - Radiation (photons) emitted when a charged particle (usually e-) is slowed or deflected by E field of another charged particle (usually nucleus) (E- lose energy via radiation as photons and slow)

Answer 148

-dE/dx = E/Lr

Answer 149

Lr The average thickness of material that reduces the energy of an electron or positron by the exponential factor, e

Answer 150

1. Photoelectric effect - absorbed whole by atom and e- emitted 2. Compton scattering - Ph scatters off atomic e- 3. Pair production - e +/- pairs are produced in the filed of a nucleus or atomic electron - requires at least 2 Me 4. Photo-production - Low energy photons absorbed by nuclei e.g. to form hydronic state

Answer 151

1/ (n*sigma)

Answer 152

A cascade of secondary particles produced through EM interactions, with decreasing energy until photons fall below pair-production threshold

Answer 153

Scattering - Elastic - Inelastic - Quasi-elastic

Answer 154

The initial and final particles are the same but momentum is transferred.

Answer 155

These processes dominate at lower energies

Answer 156

The initial and final state particles are different.

Answer 157

These processes dominate at higher energies

Answer 158

A limiting case of inelastic scattering. Elastic interactions occur with the nucleon, that then results in nuclear recoil resulting in a de-excitation or break-up of the nucleus.

Answer 159

Energy transfer is small compared to the incident energy.

Answer 160

Interactions between hadrons (particales made of quarks such as p,n and mesons) - 1-2 femtometers - strong force

Answer 161

Sigma, which indicates the total probability of interaction, is a sum over all the elastic and inelastic process cross-section

Answer 162

P = n σtotal dx

Answer 163

lc, the mean distance travelled before an interaction

Answer 164

lc = 1/ (n σtotal)

Answer 165

L sub a, - mean distance travelled before an inelastic interaction (where the initial particle is absorbed and ceases to exist)

Answer 166

La = 1 / (n * σinelastic)

Answer 167

Lc ~ la as inelastic dominates

Answer 168

- Interactions with nuclei and neutrinos or anti neutrinos - occur via the weak interaction producing a more easily detected lepton - 1-2femotmeters

Answer 169

neutrino cross sections very small - causes very large interaction lengths

Answer 170

- E- / photons - Hadrons -Muons - neutrinos

Answer 171

Ability to pass through materials without significant absorption or deflection

Answer 172

Detection over long distances

Answer 173

Ionisation

Answer 174

Astronomical

Answer 175

1. Tracker - for tracking charged particles over short distances. - Gives accurate vertex reconstruction for particles that decay in O(cms) or less. 2. Electromagnetic Calorimeter for fully containing and reconstructing the energy of e± and photons. 3. Hadronic Calorimeter for fully containing and reconstructing the energy of hadrons. 4. Muon Systems for tracking and reconstructing the energy of muons which are the most st penetrating of the observed particle

Answer 176

Classic collider experiment

Answer 177

Type of detector in particle physics to measure r energy of EM particles such as e and p

Answer 178

A type of detector used to measure energy of hadrons when interacting with matter

Answer 179

A detector system used to identify and measure muons

Answer 180

Tracker, EM calorimeter, hadronic calorimeter, muon system - order of least to most penetrating

Answer 181

Nothing. Presence inferred from missing energy

Answer 182

Energy in particle physics which is not directly detected but inferred from conservation of energy and momentum

Answer 183

The fundamental methods or mechanism by which a particle detector identities and measures particles or radiation

Answer 184

1. Ionisation 2. Scintillation 3. Cerenkov radiation 4. Semiconductor detectors 5. Calorimetry 6. Magnetic deflection 7. Cherenkov detectors

Answer 185

Heavy charged particles

Answer 186

- Emulsion - Cloud - Bubble - Gaseous ionisation - Wire chamber - Drift chamber - Time projection chambers

Answer 187

- Tracking ionisation detectors - In photographic emulsions charged particles cause ionization along their path, which show up as linesin developed film. - Gives good tracking resolution, especially when a magnetic field is applied, - detector is always active so over an exposure you end up with many overlapping tracks.

Answer 188

- Deploys many layers of emulsion inter-spaced by passive material layers made of plastic or metal

Answer 189

- Type of ionisation detector. - The chamber is filled with water vapour under pressure. - When a charged particle traverses the chamber the ionization produced by the particle causes droplets to form about the ions revealing the particle’s track, which can be captured by photograph

Answer 190

follow a similar principle to cloud chamber sbut the detecting medium is super-heated liquid and bubbles form on the ionisation sites to reveal the particle track

Answer 191

Gargamelle

Answer 192

e.g.OPERA detector at LNGS in CERN - Pb was used between layers due to its high density to maximise the chance of neutrino interaction

Answer 193

- Collect the ionisation charge generated as a charged particle passes through a gaseous detector medium on electrodes - Gives an instantaneous electrical signal. - Gas dependent but requires approximately 30 eV to produce an electron-ion pair. - If strong electric field is applied, these pairs can then produce secondary ionisation thus amplifying the signal measured at the electrodes

Answer 194

- A form of gaseous ionisation detectors similar to drift chambers - Maintain the gas at negative potential with an applied field E (of order 104 − 105 V/cm near the wire) - The signal measured at a wire anode at positive voltage is proportional to the energy of the particle

Answer 195

Specific operating regions in some particle detectors where the number of ion pairs produced by a charged particle is directly proportional to the energy deposited by the particle

Answer 196

A gaseous ionisation detector similar to drift chambers - will have many such anode wires (spaced ∼ 2 mm apart) between common cathode plates and can achieve spatial resolutions in the range 50 − 200 µm and time resolution ∼ 2

Answer 197

multi-wire proportional chamber

Answer 198

Gaseous ionisation detectors similar to wire chambers - use the fact that the liberated electrons take time to drift from their point of production (on the particle track) to the anode. - Have many wires to provide a relatively constant electric field through the gas volume and accurately measure the drift time with respect to an external reference time

Answer 199

50-150microm

Answer 200

Time projections chambers

Answer 201

Gaseous ionisation detector - Electric field applied across a large (of order metres) volume of gas or liquid giving high precision with a low energy threshold. - Anode wires are strung in one plane (lets say along the x direction in the x − y plane) either at the end or in the middle of the z range of the volume

Answer 202

- The y position is reconstructed from the location of anode wire hit. - The x position comes from the position of the hit along the anode wire, and hence how long the signal takes to reach the readout end of the wire. - The z position comes from the time taken for the drifting charge to reach the wire. - Energy deposit dE/dx comes from the magnitude of the measured anode voltages

Answer 203

Particle identification - process of identification based on properties

Answer 204

A neutrino oscillator experiment

Answer 205

- Essentially solid state ionisation detectors. - The charged particle passes through the detector material (eg. Silicon), and releases valence electrons. - The electron and hole pairs are then collected at electrodes giving a charge signal proportional to the energy loss of the incident particle

Answer 206

- Uses materials called scintillators that emits luminescence when excited by ionizing particles. - Scintillators can be either solid or liquid. - A small fraction of the excitation energy emerges as visible or UV light

Answer 207

Material or device that absorbs light and re-emits at different (usually longer) wavelength

Answer 208

Fluorescent material incorporated into detectors to enhance detection of charge particles

Answer 209

Photomultiplier tubes

Answer 210

uses photoelectric effect - Light incident on a photocathode deposited on the inner front surface of an evacuated glass bulb releases a photo-electron - electron is picked up by a chain of electrodes with increasing potential to amplify the signal giving a measureable current pulse for each single incident photon.

Answer 211

uses solid scintillator strips arranged in layers interleaved with iron to track charged particles produced by neutrino interactions

Answer 212

Scintillator detector - uses a large volume of liquid scintillator (filling a 12 m radius acrylic vessel) observed by an array of 9300 PMTs.

Answer 213

- allows detection of neutrino interactions down to energies of <1 MeV - but the scintillation light is isotropic so does not give any direction or tracking information on the particles produced in the interactions.

Answer 214

Electromagnetic shock-wave emitted as charged particles pass through a medium with refractive index n >1

Answer 215

Speed of light in a medium reduces to c/n, due to the possible interactions with the molecules of the material

Answer 216

A relativistic charged particle can travel faster than light in the medium.

Answer 217

β > 1/n ( n = refractive index)

Answer 218

Cherenkov effect used, where the refractive index used is selected so that only particles above the required energy produce signal

Answer 219

- used in the LHCb detector at the LHC, - determine the angle of the cone emitted and hence the particle velocity. - Combined with a momentum measurement in a magnetic field, particle mass and hence identity can be determined.

Answer 220

- Excellent neutrino detectors providing a large, and cheap, detector volume. - By instrumenting the outer wall of a, usually cylindrical, tank of water with many PMTs, we can measure rings of light where the Cherenkov cone intersects with the tank wall

Answer 221

Gives energy of the charged particle,

Answer 222

information on the charged particle’s position and direction

Answer 223

how fuzzy the ring is

Answer 224

measure energy and direction of particles by total absorption.

Answer 225

destructive detectors

Answer 226

change the nature of the incoming particle, aiming to completely contain it within the calorimeter volume so that total energy is measured

Answer 227

Outside tracking and PID instrument

Answer 228

Charged and neutral, by producing charged secondaries

Answer 229

produce showers of particles e±, γ via the electromagnetic interaction through Bremsstrahlung and pair production processes.

Answer 230

produce showers of particles via the strong interaction. - These shower particles, such as neutral pions, then usually deposit energy via EM interaction

Answer 231

- Encorporate layers of absorber (dense materials such as Pb) and active detector components (such as scintillators or MWPCs). - Transverse separation of the calorimeter detector components can provide additional spatial information.

Answer 232

Uncertainty on measured energy is proportional to 1/E

Answer 233

Both sampling calorimeters

Answer 234

- the measurement in a calorimeter is relatively simple (no complicated tracking algorithms required) - fast - calorimeter information is often used for making triggering decisions.

Answer 235

composite particles made up of quarks held together by strong force

Answer 236

To leptons through weak interaction

Answer 237

Frame where net momentum = 0

Answer 238

The one where total momentum = p

Answer 239

Accelerate particle

Answer 240

Manipulate trajectory

Answer 241

Strong E field

Answer 242

Quadrupole magnets

Answer 243

Counteract electrostatics repulsion between particles

Answer 244

Dipole magnets

Answer 245

Unstable particles E.g pions

Answer 246

From Lorentz and angular acceleration, B field strength, radius of circular path and charge of particle

Answer 247

Accelerators, Metallic chambers to build up very strong EM field to give particles electrical impulse to accelerate them

Answer 248

Approx 100MHz

Answer 249

Chain of electromagnets and vacuum drift tubes

Answer 250

Contain vacuums so particles can travel unobstructed

Answer 251

Stable, charges ( E +/-, p+/-, ions)

Answer 252

Due to conservation of momentum, all energy is available and carried forward.

Answer 253

To get high energies, LINACs need longer and longer machines

Answer 254

Energy is used to boost the centre of mass forwards so less available for particle

Answer 255

Revolution frequency = c/( 2* Pi* R)

Answer 256

Frequency of RF/ revolution frequency

Answer 257

Collision energy and particles involved

Answer 258

Densities and geometries of beam and target

Answer 259

Inverse area, inverse time

Answer 260

10^-15m^-2

Answer 261

Decay into muons and neutrinos?

Answer 262

Neutral, remains focused and travel in straight line. As pions travel in straight lines, decay products will too

Answer 263

Emit significant Bremsstrahlung radiation - huge energy loss needing larger and larger rings

Answer 264

Through interaction with matter

Answer 265

Curvature of path of charged particles in magnetic fields

Answer 266

Ionisation or radiation

Answer 267

Heavy particles, no electrons and positrons

Answer 268

Force potenital

Answer 269

Particle whose mean energy loss rate through matter is close to the minimum

Answer 270

-occurs when kinetic energy is at least twice larger than their rest mass

Answer 271

Photomultiplier tubes - used to detect photos in scintillation detectors ( Put photons in and get electricity out like reverse lightbulb)

Answer 272

Related to characteristic cone shape of Cherenkov detectors Geometrically - cn/t and Bct as sides of triangle

Answer 273

They can be used to determine particle velocity

Answer 274

E- positron pair production

Answer 275

Neutrinos due to high penetration

Answer 276

E=/- and photons

Answer 277

Hadrons e.g. Pion, K, protons, neutrons

Answer 278

Neutral, but via strong interaction

Answer 279

Via weak interactions

Answer 280

Interaction with ***

Answer 281

Determining the angle of the cone and therefore particle velocity

Answer 282

Smaller relative to beam direction

Answer 283

At 3.momentum = 0 = Ea + Eb

Answer 284

Lab frame is same as COM frame so S = 4E^2

Answer 285

Objects in rest frame appear shorter from moving frame

Answer 286

Effective length is shortened in direction of particle velocity

Answer 287

An event in a rest frame appears to take longer from a moving frame

Answer 288

E/M or 1 / sqrt ( 1- v^2/ c^2)

Answer 289

Particles take longer to decay the faster they’re moving

Answer 290

1Gev = 0.197 X10^-15m

Answer 291

1Gev = 1.8x10^-27kg

Answer 292

1GeV = 6.58 x10^-25s

Answer 293

1Gev = 1.6 x10^-10J

Answer 294

5.39 x10^-19kg.m/s

Answer 295

C, h and hbar are unity

Answer 296

C = +1, others =0

Answer 297

B = -1, others =0

Answer 298

T = +1, others =0

Answer 299

10^-40m^-2

Answer 300

L = (n*N1N2 * f)/A - n =number of bunches (usually 4-8) N = number of particles in collimating beams F = collision frequency or revolution frequency if cyclic A = effective cross section (beam spot area)

Answer 301

esidual of the strong force that binds quarks into nucleons (at a range of < 0.8 fm

Week 6-10 Nuke Flashcards

(402 cards)