Searches for superparticles of CMSSM model at the LHC
Using the discovery of a SM-like Higgs boson by ATLAS and CMS Collaborations and the observation by CMS and LHCb of BR(Bs → μ⁺μ⁻) decay as well as 8 TeV ATLAS 20 fb⁻¹ jets + ET data set we received an indirect constraint on SUSY model parameters. Considering the constrained versions of the minimal s...
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irk-123456789-1121262017-01-18T03:03:20Z Searches for superparticles of CMSSM model at the LHC Obikhod, T.V. Ядерная физика и элементарные частицы Using the discovery of a SM-like Higgs boson by ATLAS and CMS Collaborations and the observation by CMS and LHCb of BR(Bs → μ⁺μ⁻) decay as well as 8 TeV ATLAS 20 fb⁻¹ jets + ET data set we received an indirect constraint on SUSY model parameters. Considering the constrained versions of the minimal supersymmetric extension of the Standard Model (CMSSM) we used SOFTSUSY and PROSPINO computer programs for calculations of masses and production cross sections of the superparticles, that could be discovered at the LHC. За допомогою даних відкритого ATLAS і CMS колабораціями CM-подібного бозону Хігса, вимірів CMS і LHCb колабораціями BR(Bs → μ⁺μ⁻), а також набору даних 8 TeV ATLAS 20 fb⁻¹ jets + ET, отримано непряме обмеження на параметри SUSY моделі. Розглядаючи обмежену версію Мінімальної суперсиметричної стандартної моделі (CMSSM), ми використовували комп'ютерні програми SOFTSUSY і PROSPINO для розрахунку мас і поперечних перерізів утворення суперчасток, які можуть бути відкриті на LHC. Используя данные открытого ATLAS и CMS коллаборациями CM-подобного бозона Хиггса, измерения CMS и LHCb коллаборациями BR(Bs → μ⁺μ⁻), а также набор данных 8 TeV ATLAS 20 fb⁻¹ jets + ET, получено непрямое ограничение на параметры SUSY модели. Рассматривая ограниченную версию Минимальной суперсимметричной стандартной модели (CMSSM), мы использовали компьютерные программы SOFTSUSY и PROSPINO для расчета масс и поперечных сечений образования суперчастиц, которые могут быть открытыми на LHC. 2015 Article Searches for superparticles of CMSSM model at the LHC / T. V. Obikhod // Вопросы атомной науки и техники. — 2015. — № 3. — С. 3-6. — Бібліогр.: 11 назв. — англ. 1562-6016 PACS: 11.25.-w, 12.60.Jv, 02.10.Ws http://dspace.nbuv.gov.ua/handle/123456789/112126 en Вопросы атомной науки и техники Національний науковий центр «Харківський фізико-технічний інститут» НАН України |
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Ядерная физика и элементарные частицы Ядерная физика и элементарные частицы Obikhod, T.V. Searches for superparticles of CMSSM model at the LHC Вопросы атомной науки и техники |
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Using the discovery of a SM-like Higgs boson by ATLAS and CMS Collaborations and the observation by CMS and LHCb of BR(Bs → μ⁺μ⁻) decay as well as 8 TeV ATLAS 20 fb⁻¹ jets + ET data set we received an indirect constraint on SUSY model parameters. Considering the constrained versions of the minimal supersymmetric extension of the Standard Model (CMSSM) we used SOFTSUSY and PROSPINO computer programs for calculations of masses and production cross sections of the superparticles, that could be discovered at the LHC. |
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Obikhod, T.V. |
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Obikhod, T.V. |
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Obikhod, T.V. |
| title |
Searches for superparticles of CMSSM model at the LHC |
| title_short |
Searches for superparticles of CMSSM model at the LHC |
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Searches for superparticles of CMSSM model at the LHC |
| title_fullStr |
Searches for superparticles of CMSSM model at the LHC |
| title_full_unstemmed |
Searches for superparticles of CMSSM model at the LHC |
| title_sort |
searches for superparticles of cmssm model at the lhc |
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Національний науковий центр «Харківський фізико-технічний інститут» НАН України |
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Ядерная физика и элементарные частицы |
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| citation_txt |
Searches for superparticles of CMSSM model at the LHC / T. V. Obikhod // Вопросы атомной науки и техники. — 2015. — № 3. — С. 3-6. — Бібліогр.: 11 назв. — англ. |
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Вопросы атомной науки и техники |
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| fulltext |
NUCLEAR PHYSICS AND ELEMENTARY PARTICLES
SEARCHES FOR SUPERPARTICLES OF CMSSM MODEL
AT THE LHC
T.V.Obikhod ∗
Institute for Nuclear Research, NAS of Ukraine, 03680, Kiev, Ukraine
(Received February 9, 2015)
Using the discovery of a SM-like Higgs boson by ATLAS and CMS Collaborations and the observation by CMS and
LHCb of BR(Bs → µ+µ−) decay as well as 8 TeV ATLAS 20 fb−1 jets + ET data set we received an indirect constraint
on SUSY model parameters. Considering the constrained versions of the minimal supersymmetric extension of the
Standard Model (CMSSM) we used SOFTSUSY and PROSPINO computer programs for calculations of masses and
production cross sections of the superparticles, that could be discovered at the LHC.
PACS: 11.25.-w, 12.60.Jv, 02.10.Ws
1. INTRODUCTION
One of the main goals of LHC is the discovery of
physics beyond the Standard Model. Its aim is to test
the predictions of high-energy physics: supersymme-
try, extra dimensions, dark matter, CP violation,
properties of quark-gluon plasma. Despite the lack
of positive information on any new physics, opened
at the LHC, scientists have discovered the SM-like
Higgs boson, very accurately check the widths of par-
ticle decays and specified properties of the particles
of Standard Model. This information can be used for
further predictions and more accurate searches for
new phenomena in collider experiments.
The direct supersymmetrization of the Standard
Model leads to the Minimal Supersymmetric Stan-
dard Model (MSSM). The MSSM receives indirect
support from experiment in:
1) the weak scale gauge couplings unify at MGUT
under MSSM renorm group conversion;
2) radiative corrections are consistent with
mt ∼ 173 GeV;
3) a light SM-like Higgs boson has mass within the
narrow window predicted by the MSSM.
The lack of SUSY signal at the LHC is reconciled by
models of natural supersymmetry, which are charac-
terized by light higgsinos of mass ∼ 100...300 GeV,
light third generation squarks and gluinos with mass
about 1.5 TeV.
We have used the constrained versions of the mini-
mal supersymmetric extension of the Standard Model
(CMSSM) with universal soft supersymmetry break-
ing parameters m0 for scalars and m1/2 for fermions
as well as a trilinear coupling A0 at an input grand
unification scale and tanβ – the ratio of the two vac-
uum expectation values of the Hu and Hd (Higgs sec-
tor of MSSMmodel consisting of two SU(2) doublets)
[1]. We will try to use LHC data in the context of
this model parameters.
2. OBSERVABLE DATA AS SELECTION
CRITERIA FOR THE PARAMETERS OF
CMSSM MODEL
As is known, the Z-boson mass can exist at just
91.2 GeV. The little hierarchy problem is connected
with question, how TeV values of SUSY model pa-
rameters yield Z-boson mass? The value of MZ in
the MSSM is given by
M2
Z
2
=
m2
Hd
+Σd
d − (m2
Hu
+Σu
u)tan
2β
tan2β − 1
− µ2 ,
where Σu
u, Σd
d represent the sum of various radiative
corrections. To obtain a natural value of MZ one
would like each term Ci (with i = Hd,Hu, µ) to have
an absolute value of order M2
Z/2, so we can define
the electroweak fine-tuning parameter
∆EW ≡ maxi(Ci)/(M
2
Z/2) ,
where CHu = | −m2
Hu
(tan2β − 1)| ,
CHd
= |m2
Hd
/(tan2β−1)| and Cµ = |−µ2| with anal-
ogous definitions for CΣu
u(k)
and CΣd
d(k)
. To get low
∆EW we require
| −m2
Hu
| ∼ M2
Z/2 and µ2 ∼ M2
Z/2 .
We need the model to find a set of model parameters
such that
∆EW ∼ 1− 30 .
For mSUGRA/CMSSM model a minimum
∆EW ∼ 100
has been found [2]. The radiative natural SUSY
model [3] or RNS is based on the MSSM which may
∗Corresponding author E-mail address: obikhod@kinr.kiev.ua
ISSN 1562-6016. PROBLEMS OF ATOMIC SCIENCE AND TECHNOLOGY, 2015, N3(97).
Series: Nuclear Physics Investigations (64), p.3-6.
3
be valid up to GUT scale. The sparticle spectra for
RNS models with ∆EW ≤ 30 is characterized by:
1) a low value of higgsino mass |µ| ∼ 100...300 GeV;
2) gluinos with mass mg ∼ 1...4 TeV;
3) top squarks with mt1
∼ 1...2 TeV and
mt2
∼ 2...5 TeV;
4) first/second generation squarks and sleptons with
masses m ∼ 1...8 TeV .
The RNS model with the above spec-
tra yields branching fractions BF(b → sγ) and
BF(Bs → µ+µ−) in accord with measured experi-
mental values.
The mass value of recently discovered Higgs-like
resonance at the CERN LHC [4], mh ∼ 125 GeV,
falls within the window predicted by the MSSM
model. In the MSSM for Higgs mass we have the
following expression
m2
h ≃ M2
Zcos
22β+
3g2
8π2
m4
t
m2
W
[
ln
m2
t
m2
t
+
X2
t
m2
t
(
1− X2
t
12m2
t
)]
,
where Xt = At − µ cosβ and m2
t
≃ mQ3mU3 . With
top-squark masses about 500 GeV, the radiative cor-
rections are not large to yield mh. Our goal is to de-
termine CMSSM model parameters due to the com-
prehensive picture presented by the following data:
1) the value of MZ ;
2) the value of mh;
3) low ∆EW ≤ 30;
4) respecting LHC constraints on sparticle masses;
5) the implementation of ATLAS 20 fb−1 events
with ET and from 2 to 6 jets, whereas at large
m0 ≻3000 GeV there were considered several AT-
LAS limits using different events with jets, leptons,
b-quarks and ET [5].
With the help of MasterCode [6] framework,
MultiNest tool [7], a new version of FeynHiggs 2.10.0
[8] we present the results of new CMSSM fit using the
above five inputs, considering the case of signµ ≻0.
In each parameter space in Fig.1 the best-fit point is
indicated by a star. This compilation of parameter
planes in the CMSSM model for signµ ≻0 is pre-
sented after implementing the ATLAS 20 fb−1 jets +
ET , BR(B → µ+µ−), mh. The results of the CMSSM
fit are indicated by solid lines of red color for 68 %
CL and contour that corresponds approximately to
the 95 % CL is shown as blue line.
In Table 1 are summarized the best-fit points
found in the analysis [9] of the low-mass and high-
mass regions of the CMSSM parameter space for sign
µ ≻0.
Table 1. The best-fit points found in global CMSSM
fits
Data set m0 m1/2 A0 tanβ
ATLAS 7 TeV 340 910 2670 12
ATLAS20/fb low mass 670 1040 3440 21
ATLAS20/fb high mass 5650 2100 -780 51
Fig.1. Parameter planes in the CMSSM for
µ ≻ 0 including the (m0,m1/2) plane (upper), the
(m0, tanβ) plane (middle) and the (tanβ,m1/2)
plane (lower)
3. CALCULATION OF THE MASS
SPECTRUM AND PRODUCTION CROSS
SECTION OF SUPERPARTNERS
Using the parameter sets of Table 1, restricted by
the observational data, it is possible to calculate the
mass spectrum of superpartners by application of the
computer program SOFTSUSY [10]. This spectrum
for three regions of the CMSSM parameter space is
shown in Table 2.
4
Table 2. Mass spectrum of superpartners (GeV)
mũL
mũR
m
d̃L
m
d̃R
mg̃ m
χ̃0
1
I 1844 1771 1845 1763 1997 381
II 2152 2073 2154 2064 2269 440
III 6780 6690 6780 6680 4619 943
By application of the computer program PROSPINO
[11] it is possible to calculate production cross
sections of superpartners. The results, pre-
sented in Fig.2, were obtained for NLO (next-to-
leading-order) for squark-squark (blue) and gluino-
gluino (green) production as the function of mass
of superparticles. The calculations were car-
ried out for the center-of-mass energy 14 TeV.
Fig.2. Squark-squark (blue) and gluino-gluino
(green) production cross sections as the function of
mass of superparticles for the center-of-mass energy
14 TeV
4. CONCLUSIONS
In this paper we have presented analyses of the
CMSSM with positive sign µ and all the relevant
constraints from the LHC run. From the results pre-
sented in Table 2, we see, that the masses of super-
particles exceed the lower limits on the masses mea-
sured by the LHC experiment. This fact confirms the
correctness of the selected parameter set presented in
Table 1. In Table 2 we presented the masses of possi-
ble dark matter candidate - neutralino. Thus, recent
precision measurements of B-meson decay widths
BR(Bs → µ+µ−) and BR(Bd → µ+µ−), ATLAS
and CMS measurements of the mass of the Higgs bo-
son, Z boson mass, as well as ATLAS searches for
events with ET accompanied by jets with the full 7
and 8 TeV data, lead us to the conclusion about the
rigid connection between the measured experimental
data and the properties of the new superparticles,
predicted with a relatively high probability by the
computer programs. The production cross sections
with NLO corrections for squark-squark and gluino-
gluino production as the function of mass of super-
particles have the same character, but it is different
for two final states. The calculations were carried
out for the center-of-mass energy 14 TeV, which are
of importance for future experiments at the LHC.
References
1. M. Drees and M. M. Nojiri. The Neutralino
Relic Density in Minimal N=1 Supergravity //
Phys. Rev. 1993, D47, p. 376-408 [arXiv: hep-
ph/9207234];
G. L. Kane, C. F. Kolda, L. Roszkowski and
J. D. Wells. Study of Constrained Minimal Su-
persymmetry // Phys. Rev. 1994, D49, p.6173-
6210 [arXiv: hep-ph/9312272];
S. S. AbdusSalam et al. Benchmark Models,
Planes, Lines and Points for Future SUSY
Searches at the LHC // Eur. Phys. J. 2011, C71,
1835 [arXiv: 1109.3859 [hep-ph]].
2. Howard Baer, Vernon Barger, Dan Mickelson.
Direct and indirect detection of higgsino-like
WIMPs: concluding the story of electroweak nat-
uralness // e-print arXiv: 1303.3816 [hep-ph]
(2013).
3. Howard Baer et al. Radiative natural supersym-
metry: Reconciling electroweak fine-tuning and
the Higgs boson mass // e-print arXiv: 1212.2655
[hep-ph] (2012).
4. G. Aad et al. [ATLAS Collaboration]. Observa-
tion of a new particle in the search for the Stan-
dard Model Higgs boson with the ATLAS de-
tector at the LHC // Phys. Lett. 2012, B716 ,
p.1-29;
S. Chatrchyan et al. [CMS Collaboration]. Obser-
vation of a new boson at a mass of 125 GeV with
the CMS experiment at the LHC // Phys. Lett.
2012, B716, p.30-61.
5. ATLAS Collaboration, http://cds.cern.ch/
record/1547563/files/ATLAS-CONF-2013-
047.pdf.
6. For more information and updates, please see
http://cern.ch/mastercode/.
7. F. Feroz, M.P.Hobson and M.Bridges. Multi-
Nest: an efficient and robust Bayesian inference
tool for cosmology and particle physics // Mon.
Not. Roy. Astron. Soc. 2009, 398, p.1601-1614
[arXiv: 0809.3437 [astro-ph]];
F. Feroz, K.Cranmer, M.Hobson, R.Ruiz de
Aus- tri and R.Trotta. Challenges of Profile Like-
lihood Evaluation in Multi-Dimensional SUSY
Scans // JHEP 2011, 1106, p.042 [arXiv:
1101.3296 [hep-ph]].
8. T. Hahn et al. High-precision predictions for the
light CP-even Higgs Boson Mass of the MSSM //
e-print arXiv: arXiv: 1312.4937 [hep-ph] (2013).
9. O. Buchmueller et al. The CMSSM and NUHM1
after LHC Run 1 // e-print arXiv: 1312.5250
[hep-ph] (2013).
10. B.C. Allanach. SOFTSUSY2.0: a program for
calculating supersymmetric spectra // Comput.
Phys. Commun. 2002, 143, p.305-331.
5
11. W. Beenakker, R. Hopker, and M. Spira.
PROSPINO: A Program for the Production of
Supersymmetric Particles in Next-to-leading Or-
der QCD // e-print arXiv: hep-ph/9611232
(1996).
ÏÎÈÑÊÈ ÑÓÏÅÐ×ÀÑÒÈÖ CMSSM - ÌÎÄÅËÈ ÍÀ LHC
Ò.Â.Îáèõîä
Èñïîëüçóÿ äàííûå îòêðûòîãî ATLAS è CMS êîëëàáîðàöèÿìè CM -ïîäîáíîãî áîçîíà Õèããñà, èçìåðå-
íèÿ CMS è LHCb êîëëàáîðàöèÿìè BR(Bs → µ+µ−), à òàêæå íàáîð äàííûõ 8ÒýÂ ATLAS 20 fb−1
jets + ET , ïîëó÷åíî íåïðÿìîå îãðàíè÷åíèå íà ïàðàìåòðû SUSY ìîäåëè. Ðàññìàòðèâàÿ îãðàíè÷åííóþ
âåðñèþ Ìèíèìàëüíîé ñóïåðñèììåòðè÷íîé ñòàíäàðòíîé ìîäåëè (CMSSM), ìû èñïîëüçîâàëè êîìïüþ-
òåðíûå ïðîãðàììû SOFTSUSY è PROSPINO äëÿ ðàñ÷åòà ìàññ è ïîïåðå÷íûõ ñå÷åíèé îáðàçîâàíèÿ
ñóïåð÷àñòèö, êîòîðûå ìîãóò áûòü îòêðûòûìè íà LHC.
ÏÎØÓÊÈ ÑÓÏÅÐ×ÀÑÒÈÍÎÊ CMSSM - ÌÎÄÅËI ÍÀ LHC
Ò.Â.Îáiõîä
Çà äîïîìîãîþ äàíèõ âiäêðèòîãî ATLAS i CMS êîëàáîðàöiÿìè CM -ïîäiáíîãî áîçîíó Õiãñà, âèìiðiâ
CMS i LHCb êîëàáîðàöiÿìè BR(Bs → µ+µ−), à òàêîæ íàáîðó äàíèõ 8Òå ATLAS 20 fb−1 jets +
ET , îòðèìàíî íåïðÿìå îáìåæåííÿ íà ïàðàìåòðè SUSY ìîäåëi. Ðîçãëÿäàþ÷è îáìåæåíó âåðñiþ Ìiíi-
ìàëüíî¨ ñóïåðñèìåòðè÷íî¨ ñòàíäàðòíî¨ ìîäåëi (CMSSM), ìè âèêîðèñòîâóâàëè êîìï'þòåðíi ïðîãðàìè
SOFTSUSY i PROSPINO äëÿ ðîçðàõóíêó ìàñ i ïîïåðå÷íèõ ïåðåðiçiâ óòâîðåííÿ ñóïåð÷àñòîê, ÿêi
ìîæóòü áóòè âiäêðèòi íà LHC.
6
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