Tipos de conducta adictiva

To get an optimal sensitivity to all three investigated benchmark models ofR-hadrons, staus and charginos, four different sets of sig- nal regions are defined. Depending on the simulated particle masses,

a final selection is applied on the mass mToF reconstructed through ToF measurements (andmdE/dxfrom thedE/dxmeasurement for the R-hadron searches). The lower mass thresholds of the signal regions are defined by taking the mean of the reconstructed simulated signal mass distribution and subtracting twice the resolution of the distri- bution at this mass point18

. No upper boundaries are defined for 18

Since statistics is low the lower mass limit derived from the fit can fluctu- ate. All mass requirements are taken in steps of 25 GeV for staus and charginos and 50 GeV forR-hadrons.

any signal region. Since the mass resolution is dominated by the ca- pability to accurately reconstruct the momentum, the signal regions are largely model independent.

R-hadron search Searches for R-hadrons are carried out in an MS- agnostic and a full-detector approach. The MS-agnostic analysis ig- nores all signals stemming from the MS including muon triggers. The search is thus less dependent on the precise mechanisms of R- hadron interaction with detector material, allows for charge-flip re- actions where previously charged R-hadrons become neutral in the dense calorimeter materials and furthermore provide sensitivity to smaller lifetimes. Candidates are selected through triggers onEmiss_T and the ID+Ca l o selection. The final selection requires a minimal candidate momentum p>200 GeV,βToF <0.75 andβγdE/dx<1.00. The corresponding signal regions are denotedSR-RH-MA. In the full- detector approach single-muon triggers are used in addition toEmiss_T triggers and βmeasurements from the MDTs and RPCs can be con-

sidered. Candidates have to pass the l o o s e selection. If no com- bined track candidate is found the ID+Ca l o selection is used as a fallback19

resulting in an orthogonal selection. As in the MS-agnostic 19

Note that the full-detector ID+Ca l o and the MS-agnostic selection are iden- tical with the exception of the trigger requirements since the full-detector ap- proach allows for single-muon triggers. analysis a cut of p > 200 GeV is placed on the candidate, which is

further required to possessβToF<0.75 andβγdE/dx<1.30. The des- ignation SR-RH-FD is used to identify full-detector R-hadron signal regions. In rare cases two candidates are found in the same event and the one with the larger pT is used while the other is dropped. The signal regions are defined in the two-dimensional mass space, where the final mass-dependent minimal requirementsmmin

ToF andmmindE/dxare listed in table5.8.

SR-RH-MA/SR-RH-FD

particle mass [GeV] 400 600 800 1000 1200 1400 1600 1800 2000 2200 2400 2600 2800 3000

mmin

ToF[GeV] 350 450 550 650 700 750 800 850 850 850 850 850 850 850

mmin

dE/dx[GeV] 300 400 450 550 600 650 700 700 750 750 750 750 750 750

Table 5.8: Definitions of the two- dimensional signal regions for the R- hadron searches.

Stable stau search Directly produced staus occur in pairs, which al- lows for the definition of two orthogonal signal regions depending on whether one or two candidates are found in an event. For the two- candidate regionSR-2C-FDevents have to pass the l o o s eselection. If only one candidate is identified it has to pass the strictert i g h tse- lection and ends up in the regionSR-1C-FD. Contrary to theR-hadron search the signal regions are one-dimensional and candidates are re- quired to have p > 200 GeV and βToF < 0.80 (p > 100 GeV and

βToF < 0.95) in the one candidate (two candidate) case. The mass- dependent minimal mass requirementsmmin_ToF are listed in table5.9.

Table5.9: Definitions of the one- and two-candidate signal regions for the stable stau searches. Given are the lower-mass boundsmmin_ToF. No upper- mass boundaries exist.

SR-1C-FD/SR-2C-FD

particle mass [GeV] 287 318 349 380 411 442 473 504 536 567 598

mmin

ToF[GeV] (SR-1C-FD) 250 275 300 325 350 375 400 425 450 475 500

mmin

ToF[GeV] (SR-2C-FD) 225 250 275 300 325 350 375 400 425 425 450

particle mass [GeV] 629 660 692 723 754 785 817 848 879 911

mmin

ToF[GeV] (SR-1C-FD) 500 525 550 575 600 625 650 675 675 700

mmin

ToF[GeV] (SR-2C-FD) 475 500 525 550 575 600 600 625 650 675

Chargino search The analysis strategy for charginos is identical to staus and requires either two candidates passing thel o o s eselection for signal regionsSR-2C-FD with p > 100 GeV and βToF < 0.95, or onet i g h t candidate for the_SR-1C-FD regions where the candidate is required to have p > 200 GeV andβToF <0.80. The lower signal region boundaries are given in table5.10.

Table5.10: Definitions of the one- and two-candidate signal regions for the chargino searches. Given are the lower- mass borders mmin

ToF. No upper-mass

boundaries exist.

SR-1C-FD/SR-2C-FD

particle mass [GeV] 200 250 300 340 400 450 500 550 600 650 700

mmin

ToF[GeV] (SR-1C-FD) 175 225 250 300 350 375 425 450 500 525 550

mmin

ToF[GeV] (SR-2C-FD) 150 200 225 275 325 350 400 425 450 500 525

particle mass [GeV] 750 800 850 899 950 1000 1100 1200 1300 1400 1500

mmin

ToF[GeV] (SR-1C-FD) 600 625 675 700 725 750 825 875 925 975 1025

mmin

ToF[GeV] (SR-2C-FD) 575 600 625 675 700 725 800 850 900 975 1025

A summary of the required cuts on the main observables momen- tum,βToF andβγdE/dxfor each of the four signal regions is given in table5.11.

[GeV] region pmin _βmax

ToF βγmaxdE/dx |η|max

SR-RH-MA 200 0.75 1.00 1.65

SR-RH-FD 200 0.75 1.30 2.00

SR-1C-FD 200 0.80 1.65

SR-2C-FD 100 0.95 2.00

Table5.11: Summary of momentum p, βToF,βγdE/dx and|η|requirements for

each of the four signal regions.