LHC`de Yeni Ağır Kuarkların Araştırılması

LHC’de Yeni Ağır Kuarkların
Araştırılması
Orhan Çakır
AU & IAU
Ankara YEF Günleri 2015, ODTU, Ankara
İçerik
Parçacık çeşitliliği
Yeni parçacıklar / yeni etkileşmeler
Yeni ağır kuarkların araştırılması
Modelden bağımsız araştırmalar
Sonuç ve Yorum
2
Parçacık Çeşitliliği
Kozmik ışın deneylerinde keşfedildiği zaman,
elektron ile benzer özelliklere sahip daha ağır
yeni bir parçacık ”muon” için I.I. Rabi sürprizle
“who ordered that?” demişti. Çünkü, muonun
nükleer fizikte bir rolü olmadığı düşünülüyordu.
Kuark ve leptonların 3 ailesi bilindikten sonra
bugün “neden daha fazla olmasın?” diye de
sorulabilir.
Yeni ağır fermiyonların çarpıştırıcılarda araştırılması için bazı
motive eden nedenler: (i) evrendeki madde-antimadde
asimetrisinin olası açıklaması (daha fazla CP kaynağı), (ii) fermiyon
kütle hiyerarşisine bir açıklama (yüksek enerjilerde demokrasi ve
bilinen spektrum için dinamik mekanizma), (iii) EW simetri
kırılmasına yeni bir bakış, (iv) karanlık madde adayı sağlaması.
3
Yeni Parçacıklar / Yeni Etkileşmeler
Standart Model Ötesinde yeni fermiyon
araştırmaları için
Modele bağımlı araştırma (model
parametreleri)
4G (SM, SM-genişletilmeleri)
VLQ (küçük Higgs modeli, kompozit
Higgs modeli, ek boyutlar, E6 model,
çeşni simetrik model, …)
Modelden bağımsız araştırma (etkin köşeler
tanımlanır)
4
Higgs
bozonu
SM
bulmacasını tamamlamış
olsa bile SM’in de daha
büyük
bir
kozmik
bulmacanın son parçası
olmadığı düşünülebilir
quarks will
be suppressed
by the elements
(fourth row structure
and/or fourth
the 4×4
nfamily
considering
a sequential
repetition
of the generation
of column)
the SM,ofthe
mily
quark pairs
already
be produced at the
Large Hadron
Collider
(LHC) at
an initial
center
of
√
on content
andcangauge
transformation
properties
are
well
defined.
The
fourtheV and an initial luminosity of L = 1031 cm−2 s−1 . At the nominal center of mass energy s = 14
ation quarks
and−1leptons should obey the chiral
structure
of the theory, or in other −1
33
−2
34
−2
−1
will be 10 cm s which will later increase to 10 cm s corresponding to 10 and 100 fb per
s, the left-handed components of the new quarks and leptons would transform as a
)sent
doublet
under
electroweak
gaugeproduction
group, while
the right-handed
components
an analysis
of the
the anomalous
resonant
of t ′ quarks
at the LHC. Here,
we assume the c
d
transform
as a(via
SU (2)
singlet.
Conventionally
the new fourth-generation
ominated
channel
charged
currents)
in which the magnitude
of Vt ′ q is important,fermions
leading to a fina
ous
production.
fast simulation
performed for theparticles
detector effects
the signal and background
enoted
by the Asymbols
of the isthird-generation
with aonprime:
4Gpeak
çerçevesinde
yeni GeV
ağırwith
fermiyonların
sınıflandırılması
variant mass
in the interval 300-800
the final state containing
W ± b jet can be interpre
✓ 0◆
alous resonant production.
t
0
0
fourth-generation
quarks
:
,
t
,
b
yeni ağır kuarklar
b0 L R R
✓ ◆
⌫⌧ 0
II.
FOURTH FAMILY QUARK INTERACTIONS
0
0
yeni ağır
leptonlar
fourth-generation leptons :
,
⌫
,
⌧
0
⌧,R
R.
⌧ L
Yeni Ağır Kuarklar
ks can couple to charged weak currents by the exchange of W ± boson, neutral weak currents by Z 0
4Ghave
kuarkların
etkileşmeleri
Lagrangian
currents
by
photon
exchange
and strong
colour (boyut-4)
currents
the için
gluons.
We include
the fourth f
enetic
particles
the same
quantum
numbers
as theirbylower-generation
cousins,
framework
(primed)
of the SM. The quark
interaction
lagrangianhas
is given
by charge +2/3 and
the up-type
fourth-generation
t0 (t-prime)
electric
yoğunluğu
0
own-type fourth-generation
quark
b
1/3. foton ve
′ µ ′ (b-prime) has′ charge
′
a µ ′ a
L = −ge ∑ Qei Qi γ Qi Aµ − gs ∑ Qi T γ Qi Gµ
s explained in Section′ 1.1.2,
the unitary CKM
matrix in generation space deterQi =b′ ,t ′
Q′i =b′ ,t ′
s the mixing of the quark gmass eigenstates
to
form
the
weak-interaction
eigen′ µ i
e
Z bozonu ile
i 5
′ 0
−
Q
γ
(g
−
g
γ
)Q
Z
s. Promoting the CKM
matrix from
toi aµ 4 ⇥ 4 matrix results
∑′ a′ 3i ⇥ 3Vmatrix
A
2 cos θw sin θw Q′ =b
,t
i
0
1
0
1 0
1
g
W bozonu ile
dweak − √ e Vud ∑
Vus VVi jubQ′ γ µV(1
d±
ub0− γ 5 )q jW
mass
i
µ + h.c.
B sweak C 2 2 B
sin θVwcdQ′ V=b
′ ,t ′ Vcb
0 C B smass C
V
cs
cb
B
C =B
C B
C .
i̸= j
(1.30)
@ bweak A
@ Vtd Vts Vtb 5 Vtb0 A @ bmass A
Teorik ve Deneysel Sınırlamalar
Nereden Geliyor?
CKM matris üniterliği
Elektrozayıf duyarlı veriler
Doğrudan ölçümler
Teorik üniterlik ve perturbatif sınır
Higgs bozonu araştırmaları
6
′
′ ′→ γ
′
′ ′ →
γ
′ >
b’ Kuark Kütle Sınırlamaları
′
′
′
′ →
ℓ ℓ−
•′
ℓ ℓ−
>
Çift üretim için kütle sınırları (PDG2014)
>
>
>
>
>
>
! !
!η! <
′ →.
>
>
>
>
>
′
′ →
′ →
′
>
>
• • •
>
•>′
>
>
>
>
>
>
>
′
′
τ
′
′ ′
• • •
α
′ →
′ →
′ →
′ →
→ ′ ′ → ′
′ →
κ
′" →′
→′ > ′ →
√′
′ →
κ
" ′ ′→ Zb
′ →
′ →
′ → γ
Tek üretim için kütle sınırları (PDG2014)
,
−
′
′
7
′
′
t’ Kuark Kütle Sınırlamaları
′
′•
Çift üretim için kütle sınırları (PDG2014)
′
′
′
′
>
>
>
>
>
>
>
→
→
→
→
′ →
′
′
• • •
•
>′ Tek
>
>>
>
>>
>
>
>
üretim için kütle sınırları
−
′
8
<
′
′ ′ →
−
ℓ ν ℓ− ν
• • •
(PDG2014)
′ →
′ →
′ ′
→ ′
→ ′→
′ ′
′ → −
κ
! ′ →
′ →′
<
→
→
′ →√
′ →
κ
! ′
′ →
′ →
<
→
<
<
<
<
<
<
<
<
<
g1, we have de′
10 ) 0:04
√ e
parametrization 0.80
by replacing has !min =d:o:f slightly larger −than
Vi j Qi γ µ (1 − γ 5 )q jW
∑
2 2 sin θw Q′ with
cided to keep this fit, since the predictions
′ ,t ′ this
11 ) 0:03
0.93
i̸= j =b V
cb0 ¼ c14 s24
0 nicely match with the data.
mass
of: m
# ¼: "#;
~
$¼
"t$:
~
(3.6)
11 ) 0:02
1.17
where gein
is mind
the electromagnetic
coupling
gs is the strong
coupling consta
Having
all the facts
above,constant,
we conclude
that our
#i
11 ) 0:02
1.45
0 −boson and W ± −boson, respectively. Q is)
s
e
denote
photon,
gluon,
Z
the
electric
c
ei
24
0
best
fits
are
obtained
for
300
&
m
&
700,
with
the
fitted
For
the
case
of
four
generations
we
have
to
determine
first
11 ) 0:02
1.76
Gell-Mann matrices. The gV and gA aret the couplings for vector and axial-vector n
D† . The
parameters
given of
in the
Table
II,V Uwhile
the
selected 4V
11 ) 0:02
2.07i.e. the
elements Vin
as: V
=
VCKM
corresponding
×CKM
4 CKM matrix is
the possible size,
power
new
i j are"expressed
Karışım Sınırlamaları
( ðx24
matrix
elements
are
presented
in
Table
III.
matrix elements. With the results of the previous section ⎛
⎞
The
final
results
at
95%
confidence
level
of
the
complete
′
V
V
V
V
us
ud
ub
ub
we=d:o:f
obtain:
ith !2min
! 1 for mt0 >
¼
Vcd Vcs Vcb )
Vcb′c⎟
4 ' 4 fitted matrices are given below: V = ⎜
24
CKM4
üniterliğinden:
⎝V V V V ′ ⎠
large su ¼ sin"u mixing angle
ts
td
tb
tb
"
1 3
2 ≈3:2"3( 1
þ low en
(≈
'
0:0535≈1:05"
'
0:0364
0:7"
$68:9
i 3 CKM
$12:4
i
The
magnitude
of
the
3
×
matrix
elements
are
determined
from
the
0:9742
0:2257
0:0035e
0:0018e
6 8
1
2ud | = 0.97418 ± 0.00027, |Vus1| = 0.2255
are |V
(2 ± 0.0019, |Vcd | = 0.230 ± 0.011, |Vc
Conservative
bound
normal
sınırlama
the 4th
2
0 Family IV
Aggressive
bound
güçlü sınırlama
Vt ′ d Vt ′ s Vt ′ b Vt ′ b′
jVub0 j
0j
29:8
i C Yeni Param.
jVcbB
' 0:144 ≈ 0:6"0:9732
≈ 2:8"
'
0:104
≈
0:46"
≈
2"
$0:2255
0:0414
0:0102e
C
B
|Vub | = 0.00393 ± 0.00036, |Vtd | = 0.0081 ± 0.0006,
|Vts | = 0.0387
± 0.0023 (assum
C
;
(2.27)
0 GeVÞjV
¼B
1
1
(
(
$24:1 ≈
i 3:0"
0j
' 0:672
'0:9649
0:671
≈ 3:0"
A CL.Önerisi:
fromi the single
top production
|Vtb0:2589
| > 0.74 at 95%
[1]. In the fourth(
family
tb@
0:0086e
$0:0416e0:7
ðx2 c
(i
18:9
$0:0019e
2
2
24
2
(i
calculated
as |Vub′ | = 0.0008, |Vcb′ | = 0.0295 and |Vtb′ | = 0.4054. For the first thr
69:3
0:0052e |V ′ |2 = 0.0315
$0:2591
0:9658
|V
| λ4-i for th
and |Vt ′ b |2 = 0.4053. We see that
there
loosei4constraint
i4|is=a |A
ts
quarks. In this case, these( bounds can be relaxed
to
an uncertainty level. If4-j
there is a
1
(
|V
|
=
|A
|
λ
$68:9
i most probably
i third
4j family quarks.
4j
body decays
occur
into the
Inspiring fr
0:2256the two 0:0036e
0:0164e$87:4
propose
a parametrization
of these matrix elements that
e gets We
(λ :=
Vus = 0.2255)
Bobrowski2009
manifestly
respects the above bounds:
0
0:9740
(i)
For
the mixing of first3 ×and
fourth
we define
(i C
3 CKM
matrix,family
we could simply
consider
fourth(iii)
row andFinally,
fourth column
B
$76:1the
theof the
$0:2259
0:9728
0:0414
0:0290e
0.0001
±
0.0014
C
B
where Ai j sınırlar
can be optimizedve
for the
quark flavorsüniterliği
qC
family number an
; q j ; n is the
(2.28)
0 GeVÞ•¼ B
i and
$27:7( i
Fit
sonuçları:
deneysel
CKM4
A
@
significantly
′
′
+
0:0092e
$0:0414
0:9932
2
3 We consider
the decay width of t0:1079
quark through t → W q including the final state
#i!
2
Error: 0.037
≈V0.74
·
λ
≈
3.3
·
λ
(
(
14
:¼ "i ðx14$0:1082
$94:6
¼ is140:0310e
e
# iy14 Þ
ub0 89:9
$0:0091e
0:9935
the mixing an
varsayımı
−0.0020 ± 0.0055
qffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi
2 m3
'
αsine
e |VQ q | s
1
0
1
(
(
Q in th
34
′
2
2
2
$68:9
i
$81:1
i
λW λr
Γ(Q → W q) =
2s
0:9740
0:2256
0:0035e
0:0160e
x
¼
"
þ
y
)
2
2
14
16 sin θW mW that
Error: 0.074
∝ 1.5 · λ
14
14
B
$71:8( i C It is obvious
$0:2259
0:9726
0:0414
0:0329e
C
B
2
2
C
B
; confusing;
(2.29) see (3.8
0 GeVÞ
¼
(i
(i
−0.13 ±
$27:1
6:0
Eilam2009
x
þ
y
A
@ 0.13
0:0083e
$0:0416e 4 14 0:9934
0:1059
14
8
þ0:7Oð"
" (i
Þ; (3.7)
)
(i
1( i c14 ¼ 1 #
an intuitive picture
83:2
$100:4
Error: 0.36
≈
1.6
·
λ
0:0344e
$0:1062e
0:9937
$0:0080e
2
still possible effect
1
0 0.18
−0.14 ±
$68:9( i
$75:4( i
0:9741 1
0:2256
0:0035e
0:0140e
tion we want to kee
9
(
′
B
C
′
gauge
anomalies, but here, the presence of vector-like quarks does
v:cancel
=
246
GeV.
Search for vector-likethe
quarks
decaying
to lightquarks
quarkscoming from the measurements of S
existence
of leptons.
vector-like
rily
imply
the
existence
of
vector-like
Nevertheless,
such exotic
quark mixing are manifold.
The
SM
couplings
themselves
are
be literature
discussed as
in well
more[58].
detail in Section 1.3.3. Furthermore, the vector
s
have
been
studied
in
the
eike
of vector-like
quarks,
which
could
result in deviations
ininduces
elec- the very interesting decay pr
quark
model
considerations
ing
with
SM-generation
quarks
ector-like
are required
to mix
with SMbut
ones,
this
should happen
ables. Alsoquarks
the oblique
parameters
get
a↵ected,
this
would
new
heavy
quarks,
whichiswill
bethe
outlined
later
in this Section. In sce
couplings
involving
the
H
doublet
field
(this
also
case
in
regular
tart
mixing
(since
the vector-like
heavyup-type
quarks
would
couple
to gauge
bosonsmix dominantly with the third
from
the
generic
quark
extension
discussed
in
SecU
and
down-type
D
quarks
mixing).
There arefunctions).
only a restricted
amount of constraints
gauge-covariant
vector-like
cuum
polarization
The
experimental
on
ew quarks are assumed to couple
to first-generation
Even or bottom partners, and usually d
are
often
referredcouplings
to asquarks.
top [59].
partners
plets
associated
to
such
renormalizable
These
are SU (2)L
ke
quarks
coming
from
the
measurements
of
SM
couplings
will
sumptions
in an experimental
analysis1:are
unavoidable
for
pracB,
respectively.
In
this
we
will
mainly
focus
on vector-like
+2/3
1/3thesis,
+5/3
4/3
Standart
modelde
kuarkların
sağ-el
ve
sol-el
alanları
farklı
kuantum
(farklı qu
CHAPTER
New
quarks
beyond
the
three
Standard-Model
g
ublets
and
triplets
involving
fields
U
,
D
,
X
and
Y
,
where
rks
beyond
the
three
Standard-Model
generations
27
tail
in Section
1.3.3.
the vector-like
quark mixal reasons,
we aim
to beFurthermore,
asthe
much
as generation
possible
model-independent,
first
(up/down-quark
partners),
with
a search
for down
dönüşüm)
özelliklerine
sahiptir.
“Vector-like
quark”ların
sağ-el
ve
sol-el
alanları
ripts
indicate
the
electric
charge.
The
quarks
with
SM
charges
+2/3
and
ood
sensitivity
to the
the presence
of vector-like
quarks.
Several
quarks
induces
veryquarks
interesting
decay
properties
of rethese
presented
in
Chapter
5.
benzer
şekilde
dönüşür,
terminoloji
ise
ayar
bozonu
ile
etkileşmelerde
“vektör” tipli
eheereferred
to
as
up-type
and
down-type
vector-like
quarks,
respectively.
The
parameters
of the
considered
model
are made
in Section
5.1.1.
of vector-like
quarks
with
SM where
quarks
can
happen
in thedensity
right-handed
will
be outlined
later
in in
this
Section.
Ininteraction
scenarios
the
SM
quarks
can
happen
the
right-handed
sector
as
well.
It
The
relevant
terms
in
the
Lagrangian
between
bağlaşım
yapmasından
gelmektedir.
Zayıf
etkileşme
özdurumu
çoklular
aşağıdaki
ak-interaction
eigenstate
multiplets
are
n processes
are mix
described
in Section
5.1.2,
and
the resulting
signal
turns
outtriplets
that
for
new
vector-like
quark
singletsquarks
and triplets
the
mix
pe
D quarks
dominantly
with
the
third
generation,
they
ector-like
quark
singlets
and
the
mixing
angles
in
the
quarks
and
up-type
and
down-type
vector-like
can
be
written
gibi
yazılabilir:
rized
in
Section
5.1.3.
op
partners
or
bottom
partners,
and
usually
denoted
by m
T qand
right-handed
sector
are
suppressed
with
respect
to the left-handed
suppressed
with
respect
to
the
left-handed
ones
by
/m
,
Kuark
karışımı
Q
g
inglets:
UL,R , DL,R
µ
Tekli:
p
L
=
W

d
UR
thesis,
we
will
mainly
focus
on
vector-like
quark
mixing
with
interaction,U
dU
R
while
new doublets
the Thirdly,
left-handed
mixings
are
suppressed
[60–6
µ
he left-handed mixings
arefor
suppressed
[60–62].
a peSM
:
sadece
q
L
2
oublets:
(Xculiar
Uwith
)L,Rfeature
, search
(U D)
, (D Y )quarks
Çiftli: partners),
L,R
L,R
down-quark
a
for
down-type
vector-like
of
vector-like
thatg:they
do
not µobtain
their
ke quarks is that they do not obtain their mass
purelyis VLQ
via
hem
q
q
L hem de
R
+SM H field.
Zµ uUThey
uR Uare
parameters
Üçlü:
R
riplets:
(Xthe
U vacuum-expectation
D)L,R
, (U
Y )L,R . value
pter
5.
of the
allowe
value
of the SM H
field.
They
areDallowed
to have
a bare
2cos✓W
tion
terms
in the Lagrangian
density
between
first-generation
mU
gauge-invariant
mass
term
in
the Lagrangian,
because left-handed a
m
in
the
Lagrangian,
because
left-handed
and
right-handed
density
describing
the interaction
between
down-type
vector-like
21
HH,uUetkileşmeleri
uR UL + h.c.
yukarı-tipli
VLQ’ların
etkileşmeleri
aşağı-tipli
VLQ’ların
down-type
vector-like
quarks
can
be
written
as
[62,
63]:
fields transform
underit the
transformations:
ly under1/3)
theand
gauge-group
transformations:
v
charge
first-generation
quarks,covariantly
Equation (1.38),
is gauge-group
to
themodel
mechanism
quark
occurs
in the
SM org in +
the hy- µ
g by which
µ For amixing
nown
parameters
appear.
given
quark
mass,
there
Linteraction,U
= p= WM
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Leigenstates
=of p
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L
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ourth-generation
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ters, corresponding2 to the couplings to the three bosons: 
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g type
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appear
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M
where
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µafter of
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
˜
⌘

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,

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⌘

˜
µ
0
uD
W
dD
Z
(1.37)
+
Zµ uU uR UR
+
Zµ 
d
D
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R
ver,
procedure
is
more
complicated
than
obtaining
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4
⇥
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CKM
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hgiven
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the
boson
involved.
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2cos✓
multiplet are Wtherefore
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of the components
a given
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mfor
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stly,
ismass
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on
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chosen
multiplet
scenario;
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alues
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should
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order
parametreler
vely there
smallparameters
[49].
Note
that
from
an
e↵ective
SM
quarks
induces
relatively
small
mass
[49].
Note that
HH,uU uR UL + h.c.
HH,dD dR D
L + h.c. .
v
p
n Section
1.3.3,
experiments
might
constrain

=

˜simultaneously
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v down-type
ere
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Uterm
and
D
quarks
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third-generation
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oupling
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a
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Linteraction,D = p Welement

u
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uD
R
R
µ
10
VLQ
ver, cancellations among multiple new quark contributions can
ion of heavy
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represents
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ion
a heavy
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As a
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from
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nce,
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possible
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Üçüncü
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Bthe
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partners:
¯
T ! bW + / tZ / tH,
T ! bW
/ t¯Z / t¯H
(1.40)
¯ + / t¯Z / t¯H
T ! bW + / tZ / tH,
T ! ¯bW
(1.40)
¯
¯
B ! tW / bZ / bH,
B ! tW / bZ / bH.
(1.41)
¯ / bH.
¯
B ! tW / bZ / bH,
B ! t¯W + / bZ
(1.41)
•
ile karışım
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U ve
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ly mixingBirinci
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bozunum
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¯
U ! dW + / uZ / uH,
U ! dW
/ uZ
¯ / uH
¯
(1.42)
PTER 1:UNew
quarks
beyond
the
three
Standard-Model
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+
¯ + / uZ
! dW / uZ / uH,
U ! dW
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¯
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phenomenological
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T
en
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3.5).
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the
only
possible
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the
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b
quark
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X
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anching
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VLQ Bozunumları
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300
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2
2
4
λW = 1 + mW
/MQ2 ′ − 2m2q/m2Q′ + m4q /m4Q′ + m2qmW
/m4Q′ − 2mW
/m4Q′
Etkin Yüksüz Akım Etkileşmeleri
(
cay width numerically, we assume three parametrizations PI, PII and PIII for the fourth family mixi
the PI parametrization we assume the constant values |VQ′ q | = |VqQ′ | = 0.01, PII contains a dynamic
= |VQ′ q j | ≈ λ 4−n with a preferred value of λ = 0.1, and PIII has the parameters
|Vt ′ d | = 0.063, |Vt ′ s | = 0.4
arXiv:1410.5480
0.044, |Vcb′ | = 0.46, |Vtb′ | = 0.47 [22].
g neutral
current interactions
known to
be absent
tree level
in the SM.
However,kuarklar
the fourth fami
Bugünkü
deneysel are
verilere
göre
yeni atağır
kuarklar
ile bilinen
than the top quark, could have different dynamics than other quarks and they can couple to the FCN
arasındaki karışımın küçük olduğu görülmektedir, burada bozunma
enhancement in the resonance processes at the LHC. Moreover, the arguments for the anomalous intera
zayıf
öngörüsünden
daha farklı
(yeni interactio
bir
given kanalları
in [23], are yüklü
more valid
for etkileşme
t ′ and b′ quarks.
The effective Lagrangian
forolabilir
the anomalous
simetri
küçük
olmasını
açıklayabilir).
olası
anormal
ly quarks
t ′ andbu
b′ ,karışımın
ordinary quarks
q, and
the neutral
gauge bosonsÜst
V =kuarkın
γ , Z, g can
be written
explicitly
etkileşmelerindeki tartışmalar daha ağır yeni kuarklar için de geçerlidir.
qi
qi
κ
κ
γ
z
Qqi get ′ σµν qi F µν + ∑
gzt ′ σµν qi Z µν
L′a = ∑
qi =u,c,t Λ
qi =u,c,t 2Λ
t’qγ ve t’qZ
κgqi ′
gst σµν λa qi Gaµν + h.c.
+ ∑
qi =u,c,t 2Λ
t’qg
qi
κγqi
κ
′
′
z
+ ∑
Qqi ge b σµν qi F µν + ∑
gz b σµν qi Z µν
qi =d,s,b 2Λ
qi =d,s,b Λ
b’qγ ve b’qZ
κgqi
′
+ ∑
gs b σµν λa qi Gaµν + h.c.
qi =d,s,b 2Λ
b’qg
(
Gµν are the field strength tensors of the gauge bosons;
σµν = i(γµ γν − γν γµ )/2; λa are the Gell-Ma
13
r
700
4.34 17.30 69.40 0.39 1.58 6.31 0.031 0.12 0.50 0.074 (1.866)
800
4.33 17.30 69.20 0.40 1.61 6.44 0.031 0.12 0.50 0.110 (2.749)
Z
Q
q
Q
Z
2
2
2
λ2 Z =
2
−
m
/m
−
4m
′
Z 4 Q 4
q/
2
4
m
m2t /m
/m2Q′′ +
−2m
mZ4/m
(7)
− Z4m
/m4Q′′ − 6m
Q’ Anormal Üretim ve Bozunumu
4.32 17.30 69.10
0.13
0.51 0.154
2 0.412 1.64 6.54 0.032
2
2
4 (3.869)
2 2 3 2
λZ = 2 − mZ /mQ′ − 4mq /mQ′ + 2mq /m4Q′ λ−Z 6m
m
/m/m
q
Zm
Q′ −
=
2
−
Z
Q′
1000
4.32 17.30 69.00 0.41 1.66 6.63 0.032 0.13 0.52 0.210 (5.253)
900
q
Q
q
Q
The anomalous
decay wid
−2
The anomalous decay widths in different channels
are proportional
to Λin different
, and they
are
The
anomalous
decay widths
chann
6L parametrization [27]. The new heavy quarks can be produced through
its anomaarXiv:1410.5480
assumed to be dominant
for
−1
−1
uplings toassumed
the ordinary
and neutral vector
bosons>as 0.1
shown
in
Fig. 1.
toquarks
be dominant
for κ/Λ
TeV
overtothe
assumed
be charged
dominantcurrent
for κ/Λchannels.
> 0.1 TeVIn this
ov
LHC’de yeni ağır kurakların anormal bağlaşımlar
yoluyla
case, if we take
all the anom
l cross sections for the productions of new heavy quarks t′ and b′ are given in Table V
if we
take
the anomalous
equal
case, if we take all the anomalous couplingcase,
equal
then
theallbranching
ratioscoupling
will be nearly
üretimleri
için
pp—>QV+X
(burada
Q=t,
b
ve
V=g,
γ,
Z)
süreci
ble VI for the parametrization PI, PII and PIII, at the center of mass energy of 8 TeV
independent
of κ/Λ.
We ha
independent
of
κ/Λ.
We
have
used
three
parame
independent
of κ/Λ.
We
have
used
three
sets entitled PI, PII and PIII
TeV. For
an bozunumları
illustration, taking
the mass
of new
heavy
quarks
as
700parametrization
GeV the
cross
ve
için
Q’—>QV
süreci
çalışılmıştır.
For the PI
parametrization,
−1 the const
For
the
PI
parametrization,
we
assume
For
the
PI
parametrization,
we
assume
the
constant
value
κ
/Λ
=
0.1
TeV
, and PII
PI:
i
g
g
Q
Q
Q
4−i
−1
has
the 0.1λ
parameters
κi /Λ
the λ
parameters
κi /Λ
with= λ
PII:
has the parameters κi /Λ = 0.1λ4−i QTeV −1has
with
= 0.5. For
PIII= we
take TeV
the couplings
q
q
4−i
−1′
V of the new heavy
4−i width
−1
ching ratios (%) and decay
width
quark (b′Vratios
) with
only
anomalous
κ
/Λ
=
0.5λ
TeV
t
Table
I: Branching
(%)
and
decay
of
the
new
heavy
quark
(t )ofwith
with
on
4−i
−1
i
κ
/Λ
=
0.5λ
TeV
with
the
same
value
λ. T
i λ. The
PIII:index i is the generation number.
κi /Λ = 0.5λ
TeV with the same value of
−1 .
b’the
dallanma
oranları,
t’and
dallanma
oranları,
parametrization
and κ/Λ
= 0.1
interactions
for PI
parametrization
and
κ/Λ
= 0.1
TeV−1 . IPI
1:PIDiagrams
for
subprocess
gq
→
V Q TeV
withPI
anomalous
vertices
Q′ qV
and Table
Q′ QV (where
Table
and
Table
II quark
prese
I
Table
II
present
the
decay
width
and
Table I and Table II present the decay width and branching ratios of the
new
heavy
′
′
Mass(GeV)
Zd(s, b)onγd(s,
b) Γ(GeV)
be the new heavy
quark b′gd(s,
or t′ b)
depending
the type
of light (q) or Mass(GeV)
heavy
(Q ≡ t,
b)
gu(c)
gt Zu(c)
Zt γu(c) γt Γ(GeV)
′
′ interactions
t
through
anomalous
for the parame
t
through
anomalous
intera
′
t
through
anomalous
interactions
for
the
parametrization
PI,
PII
and
PIII,
respectively.
respectively).
500
30.50
2.60
0.21
0.257
500
33.5 22.9 2.86 1.82 0.92 0.63 0.23
−1
Taking
the
anomalous
coupling
κ/Λ
=
0.1
TeV
Taking
the
anomalous
coupl
−1
′
Taking the anomalous coupling κ/Λ = 0.1 TeV we calculate the t decay width Γ = 0.65
600
30.40
2.69
0.21
0.436
600
32.3 25.0 2.86 2.13 0.91 0.70 0.41
6
GeV and 1.90 GeV forGeV
mt′ and
= 700
GeV
andfor
1000
GeV
′ = 7
1.90
GeV
m
′
t
′
GeV and
1.90
GeV
for
m
=
700
GeV
and
1000
GeV,
respectively.
The
branching
into
t
→
qg
700
30.40
2.76 t 0.22
0.682
700
31.6 26.2 2.87 2.34 0.90 0.75 0.65
′
channel
is
the
largest
and
branching
into
t
→
qγbra
ch
channel
is
the
largest
and
′
channel
largest2.82
and branching
the2.89
smallest
for 0.78
equal0.97
anomalous
800 channel
31.1 is
27.0
2.48 0.90
800is the30.30
0.22
1.005into t → qγ
couplings with the parametrization PI. On the ot
couplings
with
the1.39parametr
900 other
30.7hand,
27.5 PII
2.91
2.58 PIII
0.91
0.81
900 with
30.20
2.86
0.22
1.415PI. On the
couplings
the parametrization
and
parametrization
give higher branching ratios into tV (V = g, Z, γ)
give
higher
branching
ratios
30.5 qV
27.8 (q2.93
2.66
0.83 due
1.90 to
1000
30.20
2.90ratios
0.23
give higher
branching
into 1.921
tV (V = g, 1000
Z, γ) than
= u,
c) 0.91
channels
λ4−i
factor in the parametrization.
14
factor in the parametrization
σ(
0
10
-1
10
Tesir Kesitleri
500
600
700
800
Mb’(GeV)
900
1000
arXiv:1410.5480
PIII on the new heavy quark mass
Figure 3: The cross section
for the process pp → bV + X depending
102
PI
√PII
for parameter sets PI, PII and PII at the center of mass energy s = 13 TeV.
Farklı parametrizasyonlar için sinyal tesir kesitleri
1
10
σ(pb)
Table VI: The cross sections (in pb) of new heavy quark b′ production without cuts for PI, PII and
PIII parametrizations at the center of mass energy of 13 TeV (8 TeV), respectively.
100
PI
PII
PIII
102
11.340 (3.913)
0.970 (0.285)
24.474 (7.114)
10
Mass (GeV) √
√
√
s =13 TeV (8 TeV) s =13 TeV (8 TeV) s =13 TeV (8 TeV)
PIII
PI
PII
-1
10
500
600
600
7.495 (2.410)
700
800
M0.607
(GeV)
t’
(0.162)
700
5.179 (1.546)
0.412 (0.099)
900
1
1000
σ(pb)
500
15.290 (4.09)
100
10.031 (2.483)
Figure 2: The cross
for the
process pp → tV
+ X(0.062)
depending on 6.832
the mass
for parameter sets
800 section 3.697
(1.025)
0.286
(1.566)
√
PI, PII and PIII
of (0.697)
mass energy s0.1905
= 13 TeV.
900at the center
2.707
(0.040)
4.791 (1.018)
-1
10
500
1000
2.021 (0.482)
0.137 (0.027)
3.441 (0.678)
′
Table V: The cross sections (in pb) of new heavy quark t production without cuts for PI, PII and
600
700
800
Mt’(GeV)
900
1000
PIIIA.parametrizations
at the
center pp
of →
mass
energy
13 (V
TeV=(8
Analysis of the
process
W+
bV + X
g, TeV),
Z, γ) respectively.
for t′ signal
PIII
Figure 2: The cross section
102 for the process pp → tV + X dependingPIon the mass for parame
Massprocess
(GeV) √
+
√
PII
The signal
pps =13
→ WTeV
bV(8+TeV)
X (V√s==13
g, Z,
γ) includes√the t′ exchange both in the
TeV (8 TeV) s =13 TeV (8 TeV)
PI, PII and PIII at the center of mass energy s = 13 TeV.
PI
PII
PIII
s-channel and t-channel. The s-channel contribution to the signal process would appear
1
10
16.736 (6.113)
′
itself as resonance around the t mass value in the W bV invariant mass. The t-channel
Table V: gives
The cross sections (in pb) of new heavy quark t′ production without cuts for PI,
600
10.362(3.72)
0.464 (0.159)
11.770 (4.031)
the non-resonant contribution. We consider that the W boson decays into lepton+missing
0
PIII parametrizations at
10 the center of mass energy 13 TeV (8 TeV), respectively.
700
7.825 (2.64)
0.337 (0.109)
8.502 (2.718)
transverse momentum with the branching ratio 21% and Z boson decays into dilepton with
PI
PII
PIII
800
5.961 (1.89)
0.250 (0.075)
6.276 (1.882)
Mass (GeV) √
√
√
-1
10 s =13 TeV (8 TeV) s =13 TeV (8 TeV) s =13 TeV (8 TeV)
900
4.602 (1.36)
0.189 (0.053)
4.701 (1.326)
13.733 (5.30)
0.664 (0.244)
σ(pb)
500
8
1000
3.593 (0.98)
0.144 (0.038)
3.609 (0.950)
500
600
section of t′ (b′ ) production is calculated as 8.50 pb (10.03 pb) for the parametrization PIII at 700
15
√
13.733 (5.30)
500
600
0.664 (0.244)
10.362(3.72)
700
800
0.464
(0.159)
Mb’(GeV)
7.825 (2.64)
0.337 (0.109)
16.736 (6.113)
900
1000
11.770 (4.031)
8.502 (2.718)
Benzetim Çalışmaları
arXiv:1410.5480
16000
Photon
Jet 1
Jet 2
Jet 3
14000
12000
Events / 10 GeV
Entries
Sinyal tV ve bV olayları (20k) ve arkaplan WjV ve jV olayları (1M)
CalcHEP ile üretildi; altsüreç olaylarının karışımı “event_mixer” betiği
ile yapıldı; bozunma ve hadronlaşma Pythia ile yapıldı; LHC için genel
algıç parametreleri kullanılarak benzetim PGS4 ile yapıldı;
ExRootAnalysis olay bilgilerinin dönüşümü için kullanıldı; Root ile
histogramlar ve analiz yapıldı.
Background
120
Signal
Ecm=13 TeV
mt’=700 GeV
κ/Λ=0.15/TeV
100
10000
80
8000
6000
60
4000
40
2000
0
50
100
150
200
250
300
350
400
p (GeV)
T
500
600
700
800
900
M
rec
t’
1000
(GeV)
Figure 11:16The reconstructed mass distributions for background and signal (tγ) with
700 900
800
900
MtV(GeV)
1000
Mt’(GeV)
MtV(GeV) 10
500
600
700
800
900
10
Mt’(GeV)
600
800
900
4: Invariant
mass distributions
mtV (where
V = 1000
γ, g and Z) for
g and Z)500
for PI Figure
parametrization
of700
the
10
M6:
(GeV)
arXiv:1410.5480
t’
√
Figure
The
same
as
Fig.5,
but
for
parametrizatio
Invariant mass distributions
m
(where
V
=
γ,
g
and
Z)
for
PI
parametrization
of te
−1
b’->bγ
tV
′
signal
with
κ/Λ
=
0.2
TeV
and
m
=
700
GeV
at
the
center
of
mass
t
nter of mass energy s = 13 TeV.
b’->bZ
√
b’->bg
bVparametrization
sinyal
Figure
6: 700
TheGeV
same
but
for
PII.
h κ/Λ =tV
0.2 sinyal
TeV−1 and
mt′ =
at as
theFig.5,
center
of mass
energy s = 13
TeV.
10
500
500 700
600
600 800
1
Lint(fb-1)
İncelenen Sinyal Kanalları
0
-1
500
600
700
800
Mb’(GeV)
jet
900
1000
′ bjet + j an
In
the
analyses,
we
consider
the
b
signal
to
be
b
+
γ
,
the
branching
6.7%.
In
our
analyses,
we
consider
the
t
signal in th
bγ:
t′ signal
in
the
l
+
b
+
γ
+
MET
,
The same as Fig.5, but for parametrization PII.
tγ: Figure 6: jet
′
′
′
ching
6.7%.
In
our
analyses,
we
consider
the
t
in
l but
++
bjparametrization
+ lγ=
In
the
analyses,
we
consider
the
b
signal
to
bbg:
+
γasthe
, bjet
and
b+
+
We
have
obtained
the
cross
sections
by
using
the
pseudo-rapid
re l = e,
l + bjetif+one
j +takes
METthe
and 3l + bjet Figure
+besignal
MET
channels,
where
e,MET
µ.diH
jet
jet
15:
The
same
Fig. 13,
for jet
PIII.
tg:µ. However,
′
j,γwhere
nalyses,
we
consider
the
b
signal
to
be
b
γ20
, be
b−
+e,
jµ.
and
bfor
+
dilepton.
bZ:
jet
jet a
j + of
MET
and
3l
+
b
+
MET
channels,
ljet
=
However,
ifand
one
takes
t
ctor
BR(W
→
hadrons)/BR(W
→
tZ:
We
have
obtained
the
cross
sections
by
using
the
pseudo-rapidity
cuts
|η
hadronic
W decays cuts
the signal
will
enhanced
by
factor
ofphoton,
BR(W
jet
transverse
momentum
p +>
200
GeV
jets
T
10
0.5
j,γby using the pseudo-rapidity
ave
obtained
the
cross
sections
cuts
|ηj,γ | in
< Table
2.5 an
W
decays
the
signal
will
be
enhanced
by
a
factor
of
BR(W
→
hadrons)/BR(W
lν).
transverse
momentum
cuts
p
>
20
−
200
GeV
for
jets
and
photon,
Table
PIII) parametrizations,
respectively.
Invari
T
PIII XIIIj,γfor PI (PII,
b'!"bΓ
se
momentum
cutsWe
pT|ηhave
>| 20
−
GeV
jets sections
and 0.4photon,
in Table
XII
cuts
pseudo-rapidity
<obtained
2.5200
and
j,γ
theforcross
by b'!"bZ
using
the XI
cuts(Table
pseudo-r
2
Table XIII
for
PI(where
(PII, PIII)
parametrizations,
respectively.
Invariant
mass
the
bV
V
=
γ,
g
and
Z)
system
is
shown
in
Fig.
12
for
P
10
j,γ
III
PI (PII,
PIII)
parametrizations,
respectively.
Invariant
mass
distribution
o
nd for
photon,
inthe
Table
VII
(TableVIII,
transverse
momentum
p
>
20
−
200
GeV
for
jets
and
photon,
in
ave
obtained
cross
sections
by
using
the
cuts
pseudo-rapidity
|η
|
<
2.5
an
−1
j,γ
T and
the bV (where
V = κ/Λ
γ, g =
and
system
ismshown
in Fig. 12 for PI paramet
signal with
0.2Z)
TeV
b′ = 700 GeV at the center of ma
j,γ
tively.
Invariant
mass
distribution
(where
V = γ, pgTable
and
Z) −
system
isofshown
inparametrizations,
Fig. photon,
12 for PIinparametrization
of th
IX)
for
PI
(PII,
PIII)
respectively.
Invaria
−1
esignal
momentum
>
20
200
GeV
for
jets
and
Table
VII
(TableVII
T = 0.2 TeV
with
κ/Λ
and
mb′ = 700 calculation
GeV at the that
centerthe
of optimized
mass
energy
10
It appears
from
signal
significance
tr
√
−1
Fig.κ/Λ
4 for
PI parametrization
of
the
′ =
s =413
TeV
ith
=
0.2
TeV
and
m
700
GeV
at
the
center
of mass
energy
b
the
tV
(where
V
=
γ,
g
and
Z)
system
is
shown
in
Fig.
for
PI
b’->bγ
)Itfor
PI
(PII,
PIII)
parametrizations,
respectively.
Invariant
mass
distribution
′
appears
from
signal
calculation that the optimized transverse m
√ significance
b’->bZ
is
p
>200
GeV
for
b
analyses.
T
erscenter
of
masssignificance
energy s =
13 TeV.
−1the optimized
b’->bg that
from
signal
calculation
transverse
momentum
cu
′
signal
with
κ/Λ
=
0.2
TeV
and
m
=
700
GeV
at
the
center
of
ma
where
V10 500
= γ,
g600 and
Z)
′ system is shown in Fig. t 4 for PI parametrization of t
is pT >200
GeV
for
b
analyses.
700
800
900
1000
¯b)V (where V ≡√
The
backgrounds
for
the
final
state
b(
photon, jet
′ transverseM momentum
the
optimized
(GeV)
00 GeV for b analyses.
It −1
appears
signal
significance
calculations
that the soptimized
th κ/Λ = 0.2 TeV
and mfrom
GeV
at¯the center
of mass energy
= 13 TeV
t′ = 700
The backgrounds
the final
state
b(b)Vcontour
(where
V ≡
photon,
jet
and Zforbo
in XIV. Wefor
apply
the
toof anomalous
the
final
state
photon
Figure 16: The cuts
plot
coupling and
mass of new
heavy quark b and
the
¯ following
Lint(fb-1)
Κ#%!TeV!1 "
1
b'!"bg
0.3
0
0.2
-1
0.1
500
b’
600
700
800
900
1000
Mb' !GeV"
′
Sonuçlar ve Yorum
SM çerçevesinde çift üretim süreçlerinden alınan sonuçlara göre yeni ağır
kuarkların kütle alt sınırları 700 GeV civarındadır, ve bu değer perturbatiflik
sınırının üzerindedir. SM Higgs bozonu araştırmalarında üretim ve bozunma
oranları SM3 modeli ile uyumlu bulunmuştur. Deney verilerine göre fit yaparak
minimal Higgs sektörü içeren SM4 modelinin 5σ ile dışarlandığı yayınlandı
[Eberhardt,PRL2012]. Ancak, SM4 modeli genişletilirse (THDM, HTM, vb.) bu
sınırlamanın zayıflayacağı düşünülebilir.
VLQ kütle özdurumları SM kuarklarınki ile karışabilir, QL ve QR alanları farklı
dönüşen kuarkların karşılaştığı sınırlamalardan geçebilir, bozunum özellikleri,
diğerleri ile karşılaştırıca daha az serbest parametreye sahip olması, VLQ’ların
fenomenolojik olarak çalışılması ve LHC deneylerinde araştırılması daha ilginç
olmaktadır.
Sinyal önemi hesaplarından LHC 13 TeV’de t’ ve b’ kuarkların anormal
t’
b’
bağlaşımlara duyarlılık κ /Λ=0.10/ TeV ve κ /Λ=0.15/TeV olarak elde edilmiştir.
18

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